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Crystals
Volume 12
Issue 6
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Crystals, Volume 12, Issue 6 (June 2022) – 127 articles

Cover Story (view full-size image): In the 1960s, a worldwide change in electronic devices was about to occur with the invention of integrated circuits. The chip was upon us, which instantly created the need for a revolution in visual communication displays. In the UK, a curious combination of government research facilities, electronic companies, and one small university came together in 1970 to form a consortium, and within two years, the basis for new technologies had been founded. View this paper
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21 pages, 3897 KiB  
Article
Thermodynamic Properties of 1,5-Pentanediamine Adipate Dihydrate in Three Binary Solvent Systems from 278.15 K to 313.15 K
by Liang Li, Yihan Zhao, Baohong Hou, Han Feng, Na Wang, Dong Liu, Yingjie Ma, Ting Wang and Hongxun Hao
Crystals 2022, 12(6), 877; https://doi.org/10.3390/cryst12060877 - 20 Jun 2022
Cited by 2 | Viewed by 1658
Abstract
In this work, solubility data of 1,5-pentanediamine adipate dihydrate in binary solvent systems of water + methanol, water + ethanol and water + N,N-dimethylformamide were experimentally measured via a static gravimetric method in the temperature range from 278.15 K to 313.15 K under [...] Read more.
In this work, solubility data of 1,5-pentanediamine adipate dihydrate in binary solvent systems of water + methanol, water + ethanol and water + N,N-dimethylformamide were experimentally measured via a static gravimetric method in the temperature range from 278.15 K to 313.15 K under atmospheric pressure. The results indicated that the solubility of 1,5-pentanediamine adipate dihydrate increased with the rising of temperature in all the selected binary solvent systems. For water + N,N-dimethylformamide, solubility increased as the mole fraction of water increased. However, the rising tendency changed when the temperature was higher than 303.15 K for water + methanol, and it would show a cosolvency phenomenon for water + ethanol. Furthermore, the solubility data were fitted with modified an Apelblat equation, NRTL model, combined nearly ideal binary solvent/Redlich Kister (CNIBS/R-K) model and Jouban–Acree model. The calculation results agreed well with the experimental data. Finally, the mixing thermodynamic properties of 1,5-pentanediamine adipate dihydrate in all tested solvents were calculated based on the experimental data and NRTL model. Full article
(This article belongs to the Special Issue Polymorphism in Crystals)
►▼ Show Figures

Figure 1

Figure 1
<p>Molecular structure of 1,5-pentanediamine adipate dihydrate.</p> Full article ">Figure 2
<p>Powder X-ray diffraction pattern of raw material and residual solid in mixed systems: water + DMF (<span class="html-italic">x<sub>w</sub></span> = 0.648), water + ethanol (<span class="html-italic">x<sub>w</sub></span> = 0.447) and water + methanol (<span class="html-italic">x<sub>w</sub></span> = 0.360) at T = 298.15 K.</p> Full article ">Figure 3
<p>Powder X-ray diffraction pattern of dried solid in mixed systems: water + DMF (<span class="html-italic">x<sub>w</sub></span> = 0.648), water + ethanol (<span class="html-italic">x<sub>w</sub></span> = 0.447) and water + methanol (<span class="html-italic">x<sub>w</sub></span> = 0.360) at T = 298.15 K.</p> Full article ">Figure 4
<p>Thermal analysis (TG-DSC) of 1,5-pentanediamine adipate dihydrate.</p> Full article ">Figure 5
<p>DSC of 1,5-pentanediamine adipate dihydrate after dehydration.</p> Full article ">Figure 6
<p>Polarized optical microscopy of anhydrous 1,5-pentanediamine adipate (<b>left</b>: 120.6 °C, <b>right</b>: 140.6 °C).</p> Full article ">Figure 7
<p>Mole fraction solubility of 1,5-pentanediamine adipate dihydrate in (water + methanol) mixed solvents with different mole fractions at various temperatures.</p> Full article ">Figure 8
<p>Mole fraction solubility of 1,5-pentanediamine adipate dihydrate in (water + ethanol) mixed solvents with different mole fractions at various temperatures.</p> Full article ">Figure 9
<p>Mole fraction solubility of 1,5-pentanediamine adipate dihydrate in (water + DMF) mixed solvents with different mole fractions at various temperatures.</p> Full article ">
10 pages, 1444 KiB  
Communication
Theoretical Investigation of Magneto-Electro-Elastic Piezoelectric Phononic Crystal
by Wen-Chao Bai, Yan Cao, Ben-Hu Zhou, Jian-Lin Liu, Gui-Xiang Liu, Han Zhang, Han-Zhuang Zhang and Hui Hu
Crystals 2022, 12(6), 876; https://doi.org/10.3390/cryst12060876 - 20 Jun 2022
Viewed by 1859
Abstract
We design a magneto-electro-elastic piezoelectric phononic crystal (MPPC) using a one-dimensional piezoelectric superlattice (with a 3m point group) and split-ring resonators. The effect of the split-ring resonators is to enhance the piezoelectric effect of the piezoelectric superlattices. This effect will create elastic anomalies [...] Read more.
We design a magneto-electro-elastic piezoelectric phononic crystal (MPPC) using a one-dimensional piezoelectric superlattice (with a 3m point group) and split-ring resonators. The effect of the split-ring resonators is to enhance the piezoelectric effect of the piezoelectric superlattices. This effect will create elastic anomalies and generate the phononic band gaps. These are first proposed theoretically. We calculate the transmission function of the MPPC through Transfer Matrix Method of the phononic crystal. By using the transmission function, we theoretically study the propagation properties of the acoustic waves in the MPPC. The mechanism for multifield coupling is analyzed. A type of phononic band gap is created, called the multifield coupling phononic band gap. We analyze the possibility of crystals as left-handed metamaterials. We also discuss some potential applications. Full article
(This article belongs to the Special Issue Active, Tunable and Reconfigurable Elastic Metamaterials)
►▼ Show Figures

Figure 1

Figure 1
<p>A schematic diagram of the MPPC, which is composed of a one-dimensional IPPLNC and SRRs. The positive and negative domains of the MPPC are arranged periodically along the <span class="html-italic">x</span>-axis. The arrows along the positive and negative <span class="html-italic">z</span>-axes indicate the positive and negative domains, respectively. The Mg concentrations in the positive and negative domains are 0 mol% and 7 mol%, respectively. The bottom arrow indicates the direction of y-polarized EM wave propagation. Here, only two periods of the MPPC have been shown.</p> Full article ">Figure 2
<p>Schematics of the analogy. (<b>a</b>) A usual <span class="html-italic">LC</span> circuit (with effective inductance <span class="html-italic">L</span> and the capacitance <span class="html-italic">C</span>). (<b>b</b>) SRR (with the gap size <span class="html-italic">l</span><sub>1</sub>, the thickness <span class="html-italic">l</span><sub>2</sub>, the width <span class="html-italic">l</span><sub>3</sub>, and the radius <span class="html-italic">r</span><sub>0</sub>).</p> Full article ">Figure 3
<p>Calculated the first−order (n = 1) equivalent elastic coefficient curves of the MPPC. The solid lines represent the real part of the equivalent elastic coefficients <math display="inline"><semantics> <mrow> <msubsup> <mi>C</mi> <mrow> <mn>11</mn> <mi>a</mi> </mrow> <mo>*</mo> </msubsup> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msubsup> <mi>C</mi> <mrow> <mn>11</mn> <mi>b</mi> </mrow> <mo>*</mo> </msubsup> </mrow> </semantics></math>. The functions exhibit negative values in the frequency gaps (<math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mi>O</mi> </msub> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mrow> <mi>O</mi> <mi>a</mi> </mrow> </msub> </mrow> </semantics></math>) and (<math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mi>O</mi> </msub> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mrow> <mi>O</mi> <mi>b</mi> </mrow> </msub> </mrow> </semantics></math>).</p> Full article ">Figure 4
<p>Transmission coefficient curves of the MPPC. There are two MPBGs (<math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mrow> <mi>O</mi> <mi>a</mi> <mn>1</mn> </mrow> </msub> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mrow> <mi>O</mi> <mi>a</mi> </mrow> </msub> </mrow> </semantics></math>) and (<math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mrow> <mi>O</mi> <mi>b</mi> </mrow> </msub> </mrow> </semantics></math>, <math display="inline"><semantics> <mrow> <msub> <mi>ω</mi> <mrow> <mi>O</mi> <mi>b</mi> <mn>1</mn> </mrow> </msub> </mrow> </semantics></math>) in the transmission spectrum. They result from an enhancement of the piezoelectric effect, which originates from the Ampère forces acting between the SRRs. When the longitudinal waves propagate along the <span class="html-italic">x</span>-axis of the MPPC, it will be strongly reflected as long as their frequency lies in the frequency gaps.</p> Full article ">
12 pages, 6324 KiB  
Article
Powder Extrusion Printing and Sintering Densification Behaviors of Ultrafine 98W-1Ni-1Fe Alloy Powder
by Yong Han, Xiao Wu, Xue Jiang and Yihan Yang
Crystals 2022, 12(6), 875; https://doi.org/10.3390/cryst12060875 - 20 Jun 2022
Cited by 2 | Viewed by 1526
Abstract
Powder extrusion printing (PEP) is an attractive fabrication technique for the automated mass production of engineering components with complicated shape and high-dimensional accuracy. This paper is concerned with PEP and sintering densification of ultrafine 98W-1Ni-1Fe powder. Three kinds of binder systems were designed. [...] Read more.
Powder extrusion printing (PEP) is an attractive fabrication technique for the automated mass production of engineering components with complicated shape and high-dimensional accuracy. This paper is concerned with PEP and sintering densification of ultrafine 98W-1Ni-1Fe powder. Three kinds of binder systems were designed. The influence of binder composition on the rheological behavior of the PEP feedstocks has been investigated. Results showed that all the feedstocks present pseudoplastic flow behavior. Compared with the FS-55 and FS-70 feedstocks, the FS-65 feedstock is more suitable for the PEP of ultrafine 98W-1Ni-1Fe powder due to its better comprehensive rheology and more homogeneous microstructure. The PEPed ultrafine 98W-1Ni-1Fe can be sintered to near full density at 1420 °C, which is much lower than traditional micro-scaled powder. The sintered 98W-1Ni-1Fe shows good mechanical performance due to its fine and uniform microstructure, its tensile strength can reach ~800 MPa, and its grain size is about 15 μm. Full article
(This article belongs to the Special Issue Preparation, Microstructure and Mechanical Properties of Tungsten Alloy)
►▼ Show Figures

Figure 1

Figure 1
<p>SEM images of the as-received powder (<b>a</b>), and the ball milled powder (<b>b</b>).</p> Full article ">Figure 2
<p>Geomertry dimensions of the ‘I’-shaped tensile sample.</p> Full article ">Figure 3
<p>Shear rate dependence of viscosity (<b>a</b>–<b>e</b>) and values of <span class="html-italic">n</span> (<b>f</b>) at various temperatures.</p> Full article ">Figure 4
<p>Viscosity changing with temperature at shearing rate of 178.8 s<sup>−1</sup>.</p> Full article ">Figure 5
<p>Relationship between viscosity and inverse temperature.</p> Full article ">Figure 6
<p>SEM images of fracture surfaces of green parts formed from various feedstocks: (<b>a</b>) FS-55; (<b>b</b>) FS-65; (<b>c</b>) FS-70.</p> Full article ">Figure 7
<p>Sintering relative density changing with sintering temperature.</p> Full article ">Figure 8
<p>Tensile strength changing with sintering temperature.</p> Full article ">Figure 9
<p>Fracture microstructure morphologies.</p> Full article ">Figure 9 Cont.
<p>Fracture microstructure morphologies.</p> Full article ">Figure 10
<p>Average tungsten grain sizes changing with sintering temperature.</p> Full article ">
19 pages, 8220 KiB  
Article
Trimetallic Oxides/GO Composites Optimized with Carbon Ions Radiations for Supercapacitive Electrodes
by Adil Alshoaibi, Chawki Awada, Faheem Ahmed, Raphael M. Obodo, Malik Maaza and Fabian I. Ezema
Crystals 2022, 12(6), 874; https://doi.org/10.3390/cryst12060874 - 20 Jun 2022
Cited by 5 | Viewed by 1935
Abstract
Hydrothermally synthesized electrodes of Co3O4@MnO2@NiO/GO were produced for use in supercapacitors. Graphene oxide (GO) was incorporated into the nanocomposites used for electrode synthesis due to its great surface area and electrical conductivity. The synergistic alliance among these [...] Read more.
Hydrothermally synthesized electrodes of Co3O4@MnO2@NiO/GO were produced for use in supercapacitors. Graphene oxide (GO) was incorporated into the nanocomposites used for electrode synthesis due to its great surface area and electrical conductivity. The synergistic alliance among these composites and GO enhances electrode performance, life span, and stability. The structural properties obtained from the X-ray diffraction (XRD) results suggest that nanocomposites are crystalline in nature. The synergistic alliance among these composites and GO enhances electrode performance, life span, and stability. Performance assessment of these electrodes indicates that their characteristic performance was enhanced by C2+ radiation, with the uttermost performance witnessed for electrodes radiated with 5.0 × 1015 ions/cm2. Full article
(This article belongs to the Special Issue New Trends in Crystals at Saudi Arabia (Volume II))
►▼ Show Figures

Figure 1

Figure 1
<p>(<b>a</b>) Co<sub>3</sub>O<sub>4</sub>@MnO<sub>2</sub>@NiO/GO synthesis procedure. (<b>b</b>) Schematic procedure for ion implantation.</p> Full article ">Figure 2
<p>XRD spectra of hydrothermally synthesized GO.</p> Full article ">Figure 3
<p>XRD spectra of Co<sub>3</sub>O<sub>4</sub>@MnO<sub>2</sub>@NiO/GO electrodes.</p> Full article ">Figure 4
<p>SEM micrographs of (<b>a</b>) pristine (<b>b</b>) radiation dose of 2.25 × 10<sup>15</sup> (<b>c</b>) 5.0 × 10<sup>15</sup> (<b>d</b>)7.25 × 10<sup>15</sup> (<b>e</b>) 1.0 × 10<sup>16</sup> ions/cm<sup>2</sup> and (<b>f</b>) EDS elemental composition of (<b>a</b>) Composite (<b>b</b>) O<sub>2</sub> (<b>c</b>) Co (<b>d</b>) Mn (<b>e</b>) Ni (<b>f</b>) Cl.</p> Full article ">Figure 4 Cont.
<p>SEM micrographs of (<b>a</b>) pristine (<b>b</b>) radiation dose of 2.25 × 10<sup>15</sup> (<b>c</b>) 5.0 × 10<sup>15</sup> (<b>d</b>)7.25 × 10<sup>15</sup> (<b>e</b>) 1.0 × 10<sup>16</sup> ions/cm<sup>2</sup> and (<b>f</b>) EDS elemental composition of (<b>a</b>) Composite (<b>b</b>) O<sub>2</sub> (<b>c</b>) Co (<b>d</b>) Mn (<b>e</b>) Ni (<b>f</b>) Cl.</p> Full article ">Figure 5
<p>(<b>a</b>) EDS and (<b>b</b>) FTIR Spectra of Pristine Co<sub>3</sub>O<sub>4</sub>@MnO<sub>2</sub>@NiO/GO Electrode.</p> Full article ">Figure 6
<p>Spectra of (<b>a</b>) PIXE and (<b>b</b>) RBS of Pristine Co<sub>3</sub>O<sub>4</sub>@MnO<sub>2</sub>@NiO/GO Electrode.</p> Full article ">Figure 7
<p>CV of Co<sub>3</sub>O<sub>4</sub>@MnO<sub>2</sub>@NiO/GO Electrodes for (<b>a</b>) pristine samples radiated with (<b>b</b>) 2.5 × 10<sup>15</sup>, (<b>c</b>) 5.0 × 10<sup>15</sup>, (<b>d</b>) 7.5 × 10<sup>15</sup>, (<b>e</b>) 1.0 × 10<sup>15</sup> ions/cm<sup>2</sup> energy and (<b>f</b>) EIS.</p> Full article ">Figure 8
<p>GCD Plots of Co<sub>3</sub>O<sub>4</sub>@MnO<sub>2</sub>@NiO/GO electrodes at (<b>a</b>) 1.0 A/g and (<b>b</b>) 2.0 A/g.</p> Full article ">Figure 9
<p>Plots of Specific capacitance versus scan rates of the electrodes with stability test as an inset.</p> Full article ">
18 pages, 10956 KiB  
Article
Numerical Simulation of Molten Pool Dynamics in Laser Deep Penetration Welding of Aluminum Alloys
by Jin Peng, Hongqiao Xu, Xiaohong Yang, Xingxing Wang, Shuai Li, Weimin Long and Jian Zhang
Crystals 2022, 12(6), 873; https://doi.org/10.3390/cryst12060873 - 20 Jun 2022
Cited by 3 | Viewed by 2179
Abstract
In this paper, the numerical simulation of molten pool dynamics in laser deep penetration welding of aluminum alloys was established based on the FLUENT 19.0 software. The three-dimensional transient behavior of the keyhole and the flow field of molten pool at different welding [...] Read more.
In this paper, the numerical simulation of molten pool dynamics in laser deep penetration welding of aluminum alloys was established based on the FLUENT 19.0 software. The three-dimensional transient behavior of the keyhole and the flow field of molten pool at different welding speeds were analyzed, and the influence of the welding speed on the molten pool of aluminum alloys in laser welding was obtained. The results indicated that the generation of welding spatters was directly related to the fluctuation of the diameter size in the middle of the keyhole. When the diameter in the middle of the keyhole increased by a certain extent, welding spatters occurred. When welding spatters occurred, the diameter in the middle of the keyhole became smaller. In addition, the size of the spatters at the welding speed of 9 m/min was larger than that of the spatters at the welding speeds of 3 m/min and 6 m/min. The welding spatter formed in laser deep penetration welding included: spatter created by an inclined liquid column behind the keyhole; splash created by a vertical liquid column behind the keyhole; small particles splashed in front of the keyhole. With the increase of the welding speed, the tendency of the welding spatter to form in front of the keyhole and to form a vertical liquid column behind the keyhole became weaker. When the welding speed was 9 min, only an obliquely upward liquid column appeared on the molten pool surface behind the keyhole. Compared with the welding speeds of 6 m/min and 9 m/min, the maximum flow velocity fluctuation of the molten pool at the welding speed of 3 m/min was obviously higher. Full article
(This article belongs to the Special Issue Laser Melting of Metals and Metal Matrix Composites)
►▼ Show Figures

Figure 1

Figure 1
<p>Calculation meshes of the numerical simulation in laser deep penetration welding.</p> Full article ">Figure 2
<p>Comparison of the experimental weld seam with the simulated molten pool. (<b>a</b>) the experimental weld seam cross section at a welding speed of 3 m/min; (<b>b</b>)the simulated molten pool at a welding speed of 3 m/min.</p> Full article ">Figure 3
<p>Three-dimensional transient behavior of the keyhole when the welding speed was 3 m/min: (<b>a</b>) <span class="html-italic">t</span> = 24 ms, (<b>b</b>) <span class="html-italic">t</span> = 25 ms, (<b>c</b>) <span class="html-italic">t</span> = 28.5 ms, (<b>d</b>) <span class="html-italic">t</span> = 28.8 ms, (<b>e</b>) <span class="html-italic">t</span> = 46.3 ms, (<b>f</b>) <span class="html-italic">t</span> = 46.8 ms.</p> Full article ">Figure 4
<p>Three-dimensional transient behavior of the keyhole when the welding speed was 6 m/min: (<b>a</b>) <span class="html-italic">t</span> = 17 ms, (<b>b</b>) <span class="html-italic">t</span> = 18.1 ms, (<b>c</b>) <span class="html-italic">t</span> = 18.2 ms, (<b>d</b>) <span class="html-italic">t</span> = 18.3 ms, (<b>e</b>) <span class="html-italic">t</span> = 18.4 ms, (<b>f</b>) <span class="html-italic">t</span> = 18.5 ms.</p> Full article ">Figure 5
<p>Three-dimensional transient behavior of the keyhole when the welding speed was 9 m/min: (<b>a</b>) <span class="html-italic">t</span> = 7.6 ms, (<b>b</b>) <span class="html-italic">t</span> = 7.9 ms, (<b>c</b>) <span class="html-italic">t</span> = 8 ms, (<b>d</b>) <span class="html-italic">t</span> = 12.5 ms, (<b>e</b>) <span class="html-italic">t</span> = 13.2 ms, (<b>f</b>) <span class="html-italic">t</span> = 13.4 ms.</p> Full article ">Figure 5 Cont.
<p>Three-dimensional transient behavior of the keyhole when the welding speed was 9 m/min: (<b>a</b>) <span class="html-italic">t</span> = 7.6 ms, (<b>b</b>) <span class="html-italic">t</span> = 7.9 ms, (<b>c</b>) <span class="html-italic">t</span> = 8 ms, (<b>d</b>) <span class="html-italic">t</span> = 12.5 ms, (<b>e</b>) <span class="html-italic">t</span> = 13.2 ms, (<b>f</b>) <span class="html-italic">t</span> = 13.4 ms.</p> Full article ">Figure 6
<p>Flow field of the molten pool when the welding speed was 3 m/min: (<b>a</b>) <span class="html-italic">t</span> = 24 ms, (<b>b</b>) <span class="html-italic">t</span> = 25 ms, (<b>c</b>) <span class="html-italic">t</span> = 28.5 ms, (<b>d</b>) <span class="html-italic">t</span> = 28.8 ms, (<b>e</b>) <span class="html-italic">t</span> = 46.3 ms, (<b>f</b>) <span class="html-italic">t</span> = 46.8 ms.</p> Full article ">Figure 6 Cont.
<p>Flow field of the molten pool when the welding speed was 3 m/min: (<b>a</b>) <span class="html-italic">t</span> = 24 ms, (<b>b</b>) <span class="html-italic">t</span> = 25 ms, (<b>c</b>) <span class="html-italic">t</span> = 28.5 ms, (<b>d</b>) <span class="html-italic">t</span> = 28.8 ms, (<b>e</b>) <span class="html-italic">t</span> = 46.3 ms, (<b>f</b>) <span class="html-italic">t</span> = 46.8 ms.</p> Full article ">Figure 7
<p>Flow field of molten pool when the welding speed was 6 m/min:(<b>a</b>) <span class="html-italic">t</span> = 17 ms, (<b>b</b>) <span class="html-italic">t</span> = 18.1 ms, (<b>c</b>) <span class="html-italic">t</span> = 18.2 ms, (<b>d</b>) <span class="html-italic">t</span> = 18.3 ms, (<b>e</b>) <span class="html-italic">t</span> = 18.4 ms, (<b>f</b>) <span class="html-italic">t</span> = 18.5 ms.</p> Full article ">Figure 7 Cont.
<p>Flow field of molten pool when the welding speed was 6 m/min:(<b>a</b>) <span class="html-italic">t</span> = 17 ms, (<b>b</b>) <span class="html-italic">t</span> = 18.1 ms, (<b>c</b>) <span class="html-italic">t</span> = 18.2 ms, (<b>d</b>) <span class="html-italic">t</span> = 18.3 ms, (<b>e</b>) <span class="html-italic">t</span> = 18.4 ms, (<b>f</b>) <span class="html-italic">t</span> = 18.5 ms.</p> Full article ">Figure 8
<p>Flow field of molten pool when the welding speed was 9 m/min: (<b>a</b>) <span class="html-italic">t</span> = 7.6 ms, (<b>b</b>) <span class="html-italic">t</span> = 7.9 ms, (<b>c</b>) <span class="html-italic">t</span> = 8 ms, (<b>d</b>) <span class="html-italic">t</span> = 12.5 ms, (<b>e</b>) <span class="html-italic">t</span> = 13.2 ms, (<b>f</b>) <span class="html-italic">t</span> = 13.4 ms.</p> Full article ">Figure 9
<p>Velocity contour of the molten pool when the welding speed was 3 m/min: (<b>a</b>) <span class="html-italic">t</span> = 24 ms, (<b>b</b>) <span class="html-italic">t</span> = 25 ms, (<b>c</b>) <span class="html-italic">t</span> = 28.5 ms, (<b>d</b>) <span class="html-italic">t</span> = 28.8 ms, (<b>e</b>) <span class="html-italic">t</span> = 46.3 ms, (<b>f</b>) <span class="html-italic">t</span> = 46.8 ms.</p> Full article ">Figure 10
<p>Velocity contour of the molten pool when the welding speed was 6 m/min: (<b>a</b>) <span class="html-italic">t</span> = 17 ms, (<b>b</b>) <span class="html-italic">t</span> = 18.1 ms, (<b>c</b>) <span class="html-italic">t</span> = 18.2 ms, (<b>d</b>) <span class="html-italic">t</span> = 18.3 ms, (<b>e</b>) <span class="html-italic">t</span> = 18.4 ms, (<b>f</b>) <span class="html-italic">t</span> = 18.5 ms.</p> Full article ">Figure 11
<p>Velocity contour of the molten pool when the welding speed was 9 m/min: (<b>a</b>) <span class="html-italic">t</span> = 7.6 ms, (<b>b</b>) <span class="html-italic">t</span> = 7.9 ms, (<b>c</b>) <span class="html-italic">t</span> = 8 ms, (<b>d</b>) <span class="html-italic">t</span> = 12.5 ms, (<b>e</b>) <span class="html-italic">t</span> = 13.2 ms, (<b>f</b>) <span class="html-italic">t</span> = 13.4 ms.</p> Full article ">Figure 12
<p>Relationship between laser source displacement and maximum flow velocity of the molten pool.</p> Full article ">Figure 13
<p>Force acting on the keyhole wall.</p> Full article ">Figure 14
<p>Scheme of the longitudinal section of a keyhole in laser deep penetration welding.</p> Full article ">
16 pages, 6589 KiB  
Article
Multi-Component Diffusion in the Vicinity of a Growing Crystal
by Christoph Helfenritter and Matthias Kind
Crystals 2022, 12(6), 872; https://doi.org/10.3390/cryst12060872 - 20 Jun 2022
Cited by 2 | Viewed by 1625
Abstract
Co-crystallization from multi-component solutions occurs in many solids formation processes. The measurement or simulative description of concentration courses in the fluid vicinity of a growing crystalline substrate is difficult for such systems. These are relevant with respect to developing concentrations of crystallizing components [...] Read more.
Co-crystallization from multi-component solutions occurs in many solids formation processes. The measurement or simulative description of concentration courses in the fluid vicinity of a growing crystalline substrate is difficult for such systems. These are relevant with respect to developing concentrations of crystallizing components at the solid-liquid interface due to diffusion fluxes in the solution. Concentrations may change such that unintended crystalline states can develop. With Fickian multi-component diffusion modeling we are able to simulate the timely evolution of the concentrations in the diffusion boundary layer during crystallization of various solid entities. Not only single solvate crystallization is modeled but also co-crystallization from multi-component solutions with different solvate states. The simulations are run with the assumption that diffusion limitation dominates. However, the model can be easily adapted to integration limitation. The interdependence of two diffusing components is taken into account in Fick’s multicomponent diffusion with a diffusion coefficient between these two components. We show that the consideration of so called cross-diffusion effects between dissolved materials can be neglected during crystallization of single decahydrates and during co-crystallization of anhydrous electrolytes. The presented model is also capable of fitting crystal growth kinetics with single point desupersaturation measurements in a thin film. In addition to the study of the kinetic parameters, the simulation allows the determination of the spatial concentration evolution from the single point concentration measurements. Full article
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<p>Diagram (<b>a</b>) represents concentration evolution in a slab of a solution of two components dissolved in a solvent. The special case of only one component (component 2) crystallizing while both other components do not crystallize is shown. The two non-crystallizing components level-up in the liquid phase. In Diagram (<b>b</b>), simultaneous crystallization of components 1 and 2 is depicted. Again, at the solid-liquid interface concentrations are set to equilibrium. Here, only the solvent enriches in the vicinity of the interface.</p> Full article ">Figure 2
<p>The numerical model: At <math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mi>C</mi> </mrow> </semantics></math> concentrations of crystallizing component are set to equilibrium conditions. No flux condition prevails for non-crystallizing components. At <math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mi>M</mi> </mrow> </semantics></math>, no flux condition for all components applies. The cells in between are modeled by Equation (<a href="#FD9-crystals-12-00872" class="html-disp-formula">9</a>).</p> Full article ">Figure 3
<p>Time and space evolution of molar fractions of component 1 (<b>a</b>), 2 (<b>b</b>), and 3 (<b>c</b>). Diagram (<b>d</b>) shows the development of the molar fraction <math display="inline"><semantics> <msub> <mover accent="true"> <mi>x</mi> <mo stretchy="false">˜</mo> </mover> <mi>i</mi> </msub> </semantics></math> of the dissolved components at the point <math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mi>M</mi> </mrow> </semantics></math>. Data with consideration of cross-diffusion is represented by full lines whereas the dashed lines illustrate the same case, but without cross-diffusion.</p> Full article ">Figure 4
<p>Simulated evolution in time and space of molar fractions of component 1 (<b>a</b>), 2 (<b>b</b>), and 3 (<b>c</b>) in solution. Diagram (<b>d</b>) shows the development of the molar fraction <math display="inline"><semantics> <msub> <mover accent="true"> <mi>x</mi> <mo stretchy="false">˜</mo> </mover> <mi>i</mi> </msub> </semantics></math> (<math display="inline"><semantics> <mrow> <mi>i</mi> <mo>=</mo> <mn>1</mn> <mo>,</mo> <mn>2</mn> </mrow> </semantics></math>) at <math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mi>M</mi> </mrow> </semantics></math>. Full lines represent the results with self-diffusion coefficients of: <math display="inline"><semantics> <mrow> <msub> <mi>D</mi> <mn>1</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi>D</mi> <mn>2</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>. Dashed lines show the results of reduced diffusion coefficient of component 1 (<math display="inline"><semantics> <mrow> <msub> <mi>D</mi> <mn>1</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math> and <math display="inline"><semantics> <mrow> <msub> <mi>D</mi> <mn>2</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <mn>1</mn> </mrow> </semantics></math>). Finally, dotted lines stand for reduced coefficients of both materials (<math display="inline"><semantics> <mrow> <msub> <mi>D</mi> <mn>1</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <msub> <mi>D</mi> <mn>2</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math>).</p> Full article ">Figure 5
<p>Time dependent overall mass transfer coefficient <math display="inline"><semantics> <msub> <mi>k</mi> <mrow> <mi>g</mi> <mo>,</mo> <mn>1</mn> </mrow> </msub> </semantics></math> retrieved from the simulative study in <a href="#crystals-12-00872-f005" class="html-fig">Figure 5</a> with diffusion coefficient ratios of <math display="inline"><semantics> <mrow> <msub> <mi>D</mi> <mn>1</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <msub> <mi>D</mi> <mn>2</mn> </msub> <mo>/</mo> <msub> <mi>D</mi> <mn>3</mn> </msub> <mo>=</mo> <mn>0.3</mn> </mrow> </semantics></math> (dotted lines).</p> Full article ">Figure 6
<p>Time and space evolution of molar fractions of component 1 (<b>a</b>), 2 (<b>b</b>), and 3 (<b>c</b>) in solution. Diagram (<b>d</b>) depicts the development of the concentration <math display="inline"><semantics> <msub> <mover accent="true"> <mi>x</mi> <mo stretchy="false">˜</mo> </mover> <mi>i</mi> </msub> </semantics></math> at the point <math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mi>M</mi> </mrow> </semantics></math> over time. Simultaneous crystallization of component 1 and 2 are shown with and without consideration of cross-diffusion effects. Full lines represent cases with consideration of cross-diffusion. Dashed lines show results of simulation without consideration of cross-diffusion.</p> Full article ">Figure 7
<p>Time and space evolution of molar fractions of component 1 (<b>a</b>), 2 (<b>b</b>), and 3 (<b>c</b>) in solution. Diagram (<b>d</b>) depicts the development of the concentration <math display="inline"><semantics> <msub> <mover accent="true"> <mi>x</mi> <mo stretchy="false">˜</mo> </mover> <mi>i</mi> </msub> </semantics></math> at the point <math display="inline"><semantics> <mrow> <mi>m</mi> <mo>=</mo> <mi>M</mi> </mrow> </semantics></math> over time. Simultaneous crystallization of component 1 and 2 are shown with different solvation states of either material. Full lines represent cases with no solvation building (<math display="inline"><semantics> <mrow> <msub> <mi>η</mi> <mn>1</mn> </msub> <mo>=</mo> <msub> <mi>η</mi> <mn>2</mn> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math>). Dashed lines represent the result if both components solidify as decasolvates (<math display="inline"><semantics> <mrow> <msub> <mi>η</mi> <mn>1</mn> </msub> <mo>=</mo> <msub> <mi>η</mi> <mn>2</mn> </msub> <mo>=</mo> <mn>10</mn> </mrow> </semantics></math>). The crystallization of a solvate and an ansolvate is given by dotted lines (<math display="inline"><semantics> <mrow> <msub> <mi>η</mi> <mn>1</mn> </msub> <mo>=</mo> <mn>10</mn> <mo>,</mo> <mspace width="3.33333pt"/> <mspace width="3.33333pt"/> <msub> <mi>η</mi> <mn>2</mn> </msub> <mo>=</mo> <mn>0</mn> </mrow> </semantics></math>).</p> Full article ">
15 pages, 3152 KiB  
Article
Behavior of B- and Z-DNA Crystals under High Hydrostatic Pressure
by Thierry Prangé, Nathalie Colloc’h, Anne-Claire Dhaussy, Marc Lecouvey, Evelyne Migianu-Griffoni and Eric Girard
Crystals 2022, 12(6), 871; https://doi.org/10.3390/cryst12060871 - 20 Jun 2022
Cited by 3 | Viewed by 2132
Abstract
Single crystals of B-DNA and Z-DNA oligomers were analyzed under high hydrostatic pressure and their behavior was compared to the A-DNA crystals already known. The amplitude of the base compression, when compared to the A-form of DNA (0.13 Å/GPa), was higher for the [...] Read more.
Single crystals of B-DNA and Z-DNA oligomers were analyzed under high hydrostatic pressure and their behavior was compared to the A-DNA crystals already known. The amplitude of the base compression, when compared to the A-form of DNA (0.13 Å/GPa), was higher for the Z-DNA (0.32 Å/GPa) and was the highest for the B-DNA (0.42 Å/GPa). The B-DNA crystal degraded rapidly around 400–500 MPa, while the Z-structure was more resistant, up to 1.2 GPa. Full article
(This article belongs to the Special Issue Crystalline Phases under Extreme Conditions)
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<p>Crystals of the dodeca-nucleotide B-DNA (<b>a</b>) and of the hexa-nucleotide Z-DNA (<b>b</b>). The first crystallizes as elongated needles, typically 100 × 800 μm in size, while the Z-DNA hexamer produces thicker crystals of about 200 × 400 μm in size.</p> Full article ">Figure 2
<p>A Z-DNA d(CGCGCG)<sub>2</sub> crystal in the DAC chamber seen at ambient pressure, (<b>a</b>) before and (<b>b</b>) after pressurization at 1 GPa. Although optically strongly affected by the compression cycle and the data collection, the crystal in (<b>b</b>) was still diffracting to 2.5 Å resolution when they initially diffracted up to 1.1 Å at ambient pressure.</p> Full article ">Figure 3
<p>The three DNA crystal packings. (<b>a</b>) The B-DNA dodecamer and (<b>b</b>) the Z-DNA hexamer both with their <b><span class="html-italic">c</span></b>-axis vertically oriented. (<b>c</b>) The A-DNA octamer is viewed along the <b><span class="html-italic">c</span></b>-axis showing the associations of the twisted duplexes that form a superhelix delimiting a central void channel.</p> Full article ">Figure 4
<p><b>Top</b>: Volume compressibility <span class="html-italic">V(P)</span> normalized as <span class="html-italic">V/Vo</span> for the B-dodecamer (in orange) and the Z-hexamer (in blue). In both cases, a rapid decrease is first observed at P ≤ 250 MPa, followed by a linear dependency. <b>Bottom</b>: Evolution of the corresponding normalized cell parameters showing the anisotropy of the compression. The <b><span class="html-italic">a</span></b> unit-cell parameter is in blue, <b><span class="html-italic">b</span></b> in red, and <b><span class="html-italic">c</span></b> in green. Solid lines for the B-DNA, dotted lines for the Z-DNA.</p> Full article ">Figure 5
<p>Electron densities of (<b>a</b>) B-DNA at 310 MPa (side view) and (<b>b</b>) the Z-DNA C3-G10 base-pair along the helix axis at 300 and 715 MPa. The map contouring is at the 1.5 σ level.</p> Full article ">Figure 6
<p>Superposition of the B-DNA (<b>left</b>) and Z-DNA (<b>right</b>) structures at ambient pressure (in blue) and 310 MPa and 715 Mpa, respectively (in red), showing, in both cases, the amplitude of the base compression.</p> Full article ">Scheme 1
<p>A schematic representation of the two pressure-dependent regimes of the DNA crystals as a function of increasing pressure (elastic or reversible in black, irreversible in red).</p> Full article ">
12 pages, 1392 KiB  
Article
Computational Studies of the Excitonic and Optical Properties of Armchair SWCNT and SWBNNT for Optoelectronics Applications
by Yahaya Saadu Itas, Abdussalam Balarabe Suleiman, Chifu E. Ndikilar, Abdullahi Lawal, Razif Razali, Ismail Ibrahim Idowu, Mayeen Uddin Khandaker, Pervaiz Ahmad, Nissren Tamam, Abdelmoneim Sulieman and Mohammad Rashed Iqbal Faruque
Crystals 2022, 12(6), 870; https://doi.org/10.3390/cryst12060870 - 20 Jun 2022
Cited by 16 | Viewed by 1904
Abstract
In this study, the optical refractive constants of the (5, 5) SWBNNT and (5, 5) SWCNT systems were calculated in both parallel and perpendicular directions of the tube axis by using Quantum ESPRESSO and YAMBO code. It also extended the optical behaviors of [...] Read more.
In this study, the optical refractive constants of the (5, 5) SWBNNT and (5, 5) SWCNT systems were calculated in both parallel and perpendicular directions of the tube axis by using Quantum ESPRESSO and YAMBO code. It also extended the optical behaviors of (5, 5) SWCNT and (5, 5) SWBNNT to both perpendicular and parallel directions instead of the parallel directions reported in the literature. It also looked at the effects of the diameter of the nanotube on the optical properties instead of chiral angles. From our results, the best optical reflection was found for (5, 5) SWBNNT, while the best optical refraction was found with (5, 5) SWCNT. It was observed that the SWCNT demonstrates refraction in both parallel and perpendicular directions, while (5, 5) SWBNNT shows perfect absorption in perpendicular direction. These new features that appeared for both nanotubes in perpendicular directions were due to new optical band gaps, which appear in the perpendicular directions to both nanotubes’ axis. The electron energy loss (EEL) spectrum of SWBNNT revealed the prominent π- and π + δ- Plasmon peaks, which demonstrates themselves in the reflectivity spectrum. Furthermore, little effect of diameter was observed for the perpendicular direction to both nanotubes’ axis; as such, the combined properties of (5, 5) SWBNNT and (5, 5) SWCNT materials/systems for transmitting light offer great potential for applications in mobile phone touch screens and mobile network antennas. In addition, the studies of optical properties in the perpendicular axis will help bring ultra-small nanotubes such as SWCNT and SWBNNT to the applications of next-generation nanotechnology. Full article
(This article belongs to the Special Issue Fabrication of Carbon and Related Materials/Metal Hybrids and Composites (Volume II))
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<p>(<b>a</b>) The electronic bands and (<b>b</b>) density of the states of (5, 5) SWBNNTs.</p> Full article ">Figure 2
<p>(<b>a</b>) The electronic bands and (<b>b</b>) density of the states of (5, 5) SWCNTs.</p> Full article ">Figure 3
<p>Dielectric functions of (5, 5) SWBNNT and SWCNT systems. (<b>a</b>) Imaginary dielectric for (5, 5) SWBNNT, (<b>b</b>) imaginary dielectric for (5, 5) SWCNT, (<b>c</b>) real dielectric for (5, 5) SWCBNNT, and (<b>d</b>) real dielectric for (5, 5) SWCNT.</p> Full article ">Figure 4
<p>Electron energy loss variations of (<b>a</b>) armchair (5, 5) SWBNNT and (<b>b</b>) armchair (5, 5) SWCNT structures.</p> Full article ">Figure 5
<p>Optical reflection of (<b>a</b>) armchair (5, 5) SWBNNT and (<b>b</b>) armchair (5, 5) SWCNT structures.</p> Full article ">Figure 6
<p>Optical absorptivity of (<b>a</b>) armchair (5, 5) SWBNNT and (<b>b</b>) armchair (5, 5) SWCNT structures.</p> Full article ">Figure 7
<p>UV-Vis spectra of (<b>a</b>) armchair (5, 5) SWBNNT and (<b>b</b>) armchair (5, 5) SWCNT structures.</p> Full article ">Figure 8
<p>The optical refractive index of (<b>a</b>) armchair (5, 5) SWBNNT and (<b>b</b>) armchair (5, 5) SWCNT structures.</p> Full article ">Figure 9
<p>Optical extinction of (<b>a</b>) armchair (5, 5) SWBNNT and (<b>b</b>) armchair (5, 5) SWCNT structures.</p> Full article ">
18 pages, 6518 KiB  
Article
Growth and Characterization of Second and Third Order Acentric Studies of l-Phenylalanine l-Phenylalaninium Malonate Single Crystal
by P. Sangeetha, M. Nageshwari, C. Rathika Thaya Kumari, S. Srividhya, G. Vinitha, G. Mathubala, A. Manikandan, M. Lydia Caroline, Anish Khan, Hajer S. Alorfi, Mahmoud Ali Hussein and Madhu Puttegowda
Crystals 2022, 12(6), 869; https://doi.org/10.3390/cryst12060869 - 20 Jun 2022
Cited by 6 | Viewed by 2040
Abstract
A single crystal of l-phenylalanine l-phenylalanininum malonate (LPPMA) was synthesized by slow evaporation and was subjected to nonlinear optical examination and physio-chemical characterization. Studies on single X-ray diffraction confirm the arrangement of monoclinic space group P21 which is a vital criterion [...] Read more.
A single crystal of l-phenylalanine l-phenylalanininum malonate (LPPMA) was synthesized by slow evaporation and was subjected to nonlinear optical examination and physio-chemical characterization. Studies on single X-ray diffraction confirm the arrangement of monoclinic space group P21 which is a vital criterion for the NLO phenomenon. The assessment of functional groups and diverse vibration modes responsible for the characteristics of the material was performed with an FTIR analysis. The UV-visible spectral examination found the wavelength of UV-cutoff at 233 nm and various optical parameters were evaluated. The mechanical strength and different criteria associated with it were assessed. The electric field response of the material was examined in terms of the dielectric constant, dielectric loss, ac conductivity and activation energy. The spectra of emission were detailed. The efficacy of second harmonic generation was studied. The parameters of nonlinearity were investigated to analyse the third-order acentric optical response in the LPPMA by Z-scan procedure. Full article
(This article belongs to the Special Issue New Horizons on Nanocrystalline Materials for Solar Energy Conversion and Storage)
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<p>The photograph of LPPMA.</p> Full article ">Figure 2
<p>FTIR profile of LPPMA.</p> Full article ">Figure 3
<p>(<b>a</b>) Profile of optical spectrum and (<b>b</b>) Tauc’s graph of LPPMA.</p> Full article ">Figure 3 Cont.
<p>(<b>a</b>) Profile of optical spectrum and (<b>b</b>) Tauc’s graph of LPPMA.</p> Full article ">Figure 4
<p>Variation of reflectance and extinction coefficient vs. (i) photon energy (<b>a</b>,<b>b</b>), (ii) absorption coefficient (α) (<b>c</b>,<b>d</b>). Plot of photon energy vs. (i) refractive index (n<sub>0</sub>) (<b>e</b>). (ii) electrical conductivity and optical conductivity (<b>f</b>) (iii) Electric susceptibility (χ<sub>c</sub>) (<b>g</b>).</p> Full article ">Figure 4 Cont.
<p>Variation of reflectance and extinction coefficient vs. (i) photon energy (<b>a</b>,<b>b</b>), (ii) absorption coefficient (α) (<b>c</b>,<b>d</b>). Plot of photon energy vs. (i) refractive index (n<sub>0</sub>) (<b>e</b>). (ii) electrical conductivity and optical conductivity (<b>f</b>) (iii) Electric susceptibility (χ<sub>c</sub>) (<b>g</b>).</p> Full article ">Figure 4 Cont.
<p>Variation of reflectance and extinction coefficient vs. (i) photon energy (<b>a</b>,<b>b</b>), (ii) absorption coefficient (α) (<b>c</b>,<b>d</b>). Plot of photon energy vs. (i) refractive index (n<sub>0</sub>) (<b>e</b>). (ii) electrical conductivity and optical conductivity (<b>f</b>) (iii) Electric susceptibility (χ<sub>c</sub>) (<b>g</b>).</p> Full article ">Figure 5
<p>Plot ln(α) vs. hυ for LPPMA.</p> Full article ">Figure 6
<p>(<b>a</b>–<b>e</b>) Hardness value, Meyers graph, Yield strength, Stiffness constant, Knoop hardness.</p> Full article ">Figure 6 Cont.
<p>(<b>a</b>–<b>e</b>) Hardness value, Meyers graph, Yield strength, Stiffness constant, Knoop hardness.</p> Full article ">Figure 6 Cont.
<p>(<b>a</b>–<b>e</b>) Hardness value, Meyers graph, Yield strength, Stiffness constant, Knoop hardness.</p> Full article ">Figure 7
<p>Variation of (<b>a</b>,<b>b</b>) logarithm of frequency versus dielectric constant, dielectric loss, (<b>c</b>,<b>d</b>) Logarithm of ac conductivity versus log f.</p> Full article ">Figure 7 Cont.
<p>Variation of (<b>a</b>,<b>b</b>) logarithm of frequency versus dielectric constant, dielectric loss, (<b>c</b>,<b>d</b>) Logarithm of ac conductivity versus log f.</p> Full article ">Figure 8
<p>(<b>a</b>) Emission spectra of LPPMA; (<b>b</b>) Fluorescence life time spectra of LPPMA, (<b>c</b>) Residual Fit of LPPMA.</p> Full article ">Figure 9
<p>(<b>a</b>) Closed aperture and (<b>b</b>) Open aperture (<b>c</b>) Ratio of the closed-to-open Z-scan traces of LPPMA.</p> Full article ">Figure 9 Cont.
<p>(<b>a</b>) Closed aperture and (<b>b</b>) Open aperture (<b>c</b>) Ratio of the closed-to-open Z-scan traces of LPPMA.</p> Full article ">
19 pages, 7156 KiB  
Article
Experimental Studies on Mechanical Properties and Microscopic Mechanism of Marble Waste Powder Cement Cementitious Materials
by Tongkuai Wang, Wenwei Yang and Jintuan Zhang
Crystals 2022, 12(6), 868; https://doi.org/10.3390/cryst12060868 - 19 Jun 2022
Cited by 10 | Viewed by 1983
Abstract
The resource utilization of waste stone powder is a meaningful way to realize sustainable development. This paper aims to study the influence of marble waste powder particle size and replacement cement dosage on the mechanical properties of cementitious materials and evaluate its microstructure [...] Read more.
The resource utilization of waste stone powder is a meaningful way to realize sustainable development. This paper aims to study the influence of marble waste powder particle size and replacement cement dosage on the mechanical properties of cementitious materials and evaluate its microstructure and mineral characterization by SEM and XRD. The results show that the early strength of cementitious materials is obviously improved when the dosage of marble waste powder is in the range of 0–15%, and the lifting effect of marble waste powder with a particle size of 600 mesh instead of cement on the strength and microstructure of cementitious materials is the most obvious. The replacement of cement with different particle sizes of marble waste powder found that it had low chemical activity and participated in the hydration reaction of cement, but the reaction degree was low. The smaller the particle size of marble waste powder instead of cement, the denser the early microstructure, the more obvious the nucleation phenomenon, and the more serious the agglomeration between particles. In addition, the mechanism model of marble waste powder replacing cement cementitious materials was proposed. The strength prediction function model between the material dosage and compressive strength was constructed, and the accuracy of the model was verified. Full article
(This article belongs to the Special Issue Geopolymer Composites)
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<p>Raw material test samples.</p> Full article ">Figure 2
<p>XRD of the marble waste powder.</p> Full article ">Figure 3
<p>Particle size distribution curve.</p> Full article ">Figure 4
<p>Test design and sample preparation process.</p> Full article ">Figure 5
<p>Results of 3 d of compressive strength. (<b>a</b>) Compressive strength. (<b>b</b>) Efficiency of action.</p> Full article ">Figure 6
<p>Results of 28 d of compressive strength. (<b>a</b>) Compressive strength. (<b>b</b>) Efficiency of action.</p> Full article ">Figure 7
<p>Results of 3 d of flexural strength. (<b>a</b>) Flexural strength. (<b>b</b>) Efficiency of action.</p> Full article ">Figure 8
<p>Results of 28 d of flexural strength. (<b>a</b>) Flexural strength. (<b>b</b>) Efficiency of action.</p> Full article ">Figure 9
<p>Results of the cement sample SEM for different ages.</p> Full article ">Figure 10
<p>Results of the PM1 sample SEM for different ages.</p> Full article ">Figure 11
<p>Results of the PM2 sample SEM of different ages.</p> Full article ">Figure 12
<p>Results of the PM3 sample SEM of different ages.</p> Full article ">Figure 13
<p>XRD of different samples. (<b>a</b>) XRD of p sample.(<b>b</b>) XRD of PM1 sample. (<b>c</b>) XRD of PM2 sample. (<b>d</b>) XRD of PM3 sample. Q: C-S-H. M: Ca(OH)<sub>2</sub>. N: C<sub>3</sub>S + C<sub>2</sub>S. G: CaCO<sub>3</sub>. K: C<sub>3</sub>A·CaCO<sub>3</sub>·11H<sub>2</sub>O. I: C<sub>3</sub>AH.</p> Full article ">Figure 14
<p>Comparison of the 3 d and 28 d XRD of Samples. (<b>a</b>) 3 d XRD of Samples. (<b>b</b>) 28 d XRD of Samples. Q: C-S-H. M: Ca(OH)<sub>2</sub>. N: C<sub>3</sub>S + C<sub>2</sub>S. G: CaCO<sub>3</sub>. K: C<sub>3</sub>A·CaCO<sub>3</sub>·11H<sub>2</sub>O. I: C<sub>3</sub>AH.</p> Full article ">Figure 15
<p>Mechanism of the action model of marble waste powder of the composite gel material.</p> Full article ">Figure 16
<p>Space micro unit of the hydration product. O is the central point of the hydration product. r is the radius of the spherical hydration product. a is space micro unit length size.</p> Full article ">Figure 17
<p>Mechanical calculation model of the hydration products in a microscopic space unit. (<b>a</b>) Schematic illustration of the spatial stress of hydration products. (<b>b</b>) Stress profile of hydration.</p> Full article ">Figure 18
<p><span class="html-italic">f</span>(<span class="html-italic">x</span>) fitting results.</p> Full article ">Figure 19
<p>Comparison of the theoretical and test values.</p> Full article ">
15 pages, 6618 KiB  
Article
A Numerical Simulation and Experimental Study on the Ultrafast Double-Laser Precision Cutting of Sapphire Materials
by Haibing Xiao, Wei Zhang, Yongquan Zhou, Mingjun Liu and Guiyao Zhou
Crystals 2022, 12(6), 867; https://doi.org/10.3390/cryst12060867 - 19 Jun 2022
Cited by 3 | Viewed by 2442
Abstract
To effectively improve the cutting quality of sapphire and optimize ultrafast picosecond laser cutting technology, this paper presents a new numerical simulation method and an experimental study of the ultrafast double-laser cutting of sapphire materials. The optimal cutting technology and the numerical simulation [...] Read more.
To effectively improve the cutting quality of sapphire and optimize ultrafast picosecond laser cutting technology, this paper presents a new numerical simulation method and an experimental study of the ultrafast double-laser cutting of sapphire materials. The optimal cutting technology and the numerical simulation of the temperature field of the ultrafast picosecond laser cutting of sapphire were designed independently. The principle is based on double-laser-beam cutting using an ultrashort pulse and a CO2 beam; the ultrashort pulse is focused on the material through a laser filamentous cutting head and perforated, and it moves at a speed of up to 200 mm/s to form the desired cutting line. Then, a CO2 beam is used for heating, and the principle of heat bilges and cold shrink causes the rapid separation of products. Furthermore, an SEM tester was used to characterize and analyze the microstructure and properties of sapphire materials. A microscope was used to analyze the composition of the cutting micro-area and explore the general mechanism of laser cutting sapphire. The results showed that the proposed method greatly improves efficiency and precision; in addition, the chipping size of sapphire is less than 4 μm. Full article
(This article belongs to the Special Issue Advanced Laser Technology and Applications)
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Figure 1
<p>Structure of sapphire material. (<b>a</b>) Al<sub>2</sub>O<sub>3</sub> covalent bonding. (<b>b</b>) Sapphire crystal structure. (<b>c</b>) Cutting surface of sapphire material. (<b>d</b>) Cutting schematic diagram.</p> Full article ">Figure 2
<p>The fragmentation of sapphire material under mechanical action. (<b>a</b>) 50×. (<b>b</b>) 100×. (<b>c</b>) 200×.</p> Full article ">Figure 3
<p>Schematic diagram of ultrafast double-laser-beam cutting. (<b>a</b>) Double-laser-beam cutting method; (<b>b</b>) Picosecond laser cutting; (<b>c</b>) CO<sub>2</sub> laser cutting.</p> Full article ">Figure 4
<p>The temperature simulation flow diagram.</p> Full article ">Figure 5
<p>Thermal expansion coefficient varies with temperature of sapphire crystal.</p> Full article ">Figure 6
<p>Thermal conductivity varies with temperature of sapphire crystal.</p> Full article ">Figure 7
<p>Simulation of the temperature field of brittle sapphire material based on ABAQUS. (<b>a</b>) Finite element mesh division. (<b>b</b>) Temperature curve varies with time.</p> Full article ">Figure 8
<p>Temperature field variation of sapphire laser cutting material based on ABAQUS at different times. (<b>a</b>) t = 0.1 S. (<b>b</b>) t = 0.2 S. (<b>c</b>) t = 0.3 S. (<b>d</b>) t = 0.4 S.</p> Full article ">Figure 8 Cont.
<p>Temperature field variation of sapphire laser cutting material based on ABAQUS at different times. (<b>a</b>) t = 0.1 S. (<b>b</b>) t = 0.2 S. (<b>c</b>) t = 0.3 S. (<b>d</b>) t = 0.4 S.</p> Full article ">Figure 9
<p>Temperature field variation of cut surface at 0.1 S.</p> Full article ">Figure 10
<p>Ultrafast double-laser beam cutting machine equipment. (<b>a</b>) Schematic diagram of ultrafast double-laser beam cutting. (<b>b</b>) photograph of the laser-cutting equipment.</p> Full article ">Figure 11
<p>Chipping size test analyzed by microscope.</p> Full article ">Figure 12
<p>Chipping size under varying laser powers.</p> Full article ">Figure 13
<p>Test for double-beam cutting sapphire. (<b>a</b>) Photograph of cutting micropores. (<b>b</b>) SEM scanning of microporous sapphire surface. (<b>c</b>) 3D roughness of the cut surface. (<b>d</b>) Sa roughness of the cut surface. (<b>e</b>) Roughness of the cut surface. (<b>f</b>) Ra roughness of the cut surface.</p> Full article ">
15 pages, 2556 KiB  
Article
Study on Fluorescence Properties of Green-Blue Apatite
by Qicheng Yan, Ziyuan Liu and Ying Guo
Crystals 2022, 12(6), 866; https://doi.org/10.3390/cryst12060866 - 19 Jun 2022
Cited by 1 | Viewed by 3472
Abstract
The fluorescence phenomenon of apatite is an important feature. In this paper, three apatites with uniform transition from green to blue were selected, and the fluorescence color characteristics of the samples were observed under UV fluorescent lamp and DiamondView. With 3D fluorescence technology, [...] Read more.
The fluorescence phenomenon of apatite is an important feature. In this paper, three apatites with uniform transition from green to blue were selected, and the fluorescence color characteristics of the samples were observed under UV fluorescent lamp and DiamondView. With 3D fluorescence technology, combined with LA-ICP-MS, this paper aims to comprehensively test the fluorescence phenomenon of apatite to explore the relationship between apatite fluorescence and elements and analyze the fluorescence color characteristics. With the experiments mentioned above, this paper explores the fluorescent color characteristics of gemstones and their influencing factors to improve the color system of apatite. UV and DiamondView experiments show that with the change from green to blue, apatites show weak purple–red to strong pink–purple fluorescence. The 3D fluorescence test shows that the samples have two notable fluorescence emission peaks: (1) The fluorescence peak group composed of the double fluorescence peaks around 600 nm is generated by the excitation light source at 450 and 470 nm and a weaker fluorescence peak generated by the excitation at 400 nm; (2) The fluorescence emission peak of the sample gradually becomes prominent and the intensity increases significantly near the areas where the excitation wavelength is 280–330 nm and where the emission wavelength is 380 nm. According to the LA-ICP-MS test combined with the element properties, the fluorescence peak group (1) is mainly affected by Mn2+, Sm3+, and Pr3+, which emit orange fluorescence. The fluorescence emission peak (2) is caused by Ce3+, Eu3+, Dy3+, and Tb3+, which emit purple fluorescence. The mixing of the two fluorescent colors results in violet–pink fluorescence. Full article
(This article belongs to the Topic Optoelectronic Materials)
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<p>G-1 (Green), BG-1 (Bluish-Green) and B-1 (Blue)apatite samples.</p> Full article ">Figure 2
<p>Relative spectral power distribution of Xe lamps and D65 light sources.</p> Full article ">Figure 3
<p>G-1, BG-1, and B-1 apatite fluorescence phenomena. Color under D65 (first row); Color observed in DiamondView fluorescence (second row).</p> Full article ">Figure 4
<p>(<b>a</b>) 3D fluorescence projection map of G-1 apatite, (<b>b</b>) 3D fluorescence contour map (Different colors are used to visualize the intensity of the fluorescence), (<b>c</b>) sample emission spectrum, (<b>d</b>) sample excitation spectrum.</p> Full article ">Figure 5
<p>(<b>a</b>) 3D fluorescence projection of BG-1 apatite, (<b>b</b>) 3D fluorescence contour map of sample (Different colors are used to visualize the intensity of the fluorescence), (<b>c</b>) sample emission spectrum, (<b>d</b>) sample excitation spectrum.</p> Full article ">Figure 6
<p>(<b>a</b>) 3D fluorescence projection map of blue apatite, (<b>b</b>) 3D fluorescence contour map of the sample (Different colors are used to visualize the intensity of the fluorescence), (<b>c</b>) sample emission spectrum, (<b>d</b>) sample excitation spectrum.</p> Full article ">Figure 7
<p>(<b>a</b>) Partial 3D fluorescence projection map of B-1 apatite, (<b>b</b>) partial 3D fluorescence contour map of sample (Different colors are used to visualize the intensity of the fluorescence), (<b>c</b>) partial emission spectrum of sample, (<b>d</b>) partial excitation spectrum of sample.</p> Full article ">Figure 8
<p>Normalized rare-earth element distribution map of apatite. Chondrite values come from McDonough and Sun (1995) [<a href="#B25-crystals-12-00866" class="html-bibr">25</a>].</p> Full article ">Figure 9
<p>(<b>a</b>) 3D fluorescence fitting diagram of three apatites, (<b>b</b>) emission spectra of the strongest peaks of the three apatites, (<b>c</b>) excitation spectra of the strongest peaks of the three apatites.</p> Full article ">Figure 10
<p>(<b>a</b>) Partial 3D fluorescence fitting diagram of three apatites, (<b>b</b>) partial emission spectra of three apatites, (<b>c</b>) partial excitation spectra of three apatites.</p> Full article ">Figure 11
<p>(<b>a</b>) Fluorescence color coordinates of G-1, (<b>b</b>)fluorescence color coordinates of BG-1, (<b>c</b>) fluorescence color coordinates of B-1.</p> Full article ">
14 pages, 5485 KiB  
Article
Charge State Effects in Swift-Heavy-Ion-Irradiated Nanomaterials
by Kristina Tomić Luketić, Juraj Hanžek, Catalina G. Mihalcea, Pavo Dubček, Andreja Gajović, Zdravko Siketić, Milko Jakšić, Corneliu Ghica and Marko Karlušić
Crystals 2022, 12(6), 865; https://doi.org/10.3390/cryst12060865 - 19 Jun 2022
Cited by 9 | Viewed by 2299
Abstract
The aim of this experimental work was to investigate the influence of the ion beam charge state on damage production in nanomaterials. To achieve this, we employed Raman spectroscopy, atomic force microscopy, and transmission electron microscopy to investigate nanomaterials irradiated by a 23 [...] Read more.
The aim of this experimental work was to investigate the influence of the ion beam charge state on damage production in nanomaterials. To achieve this, we employed Raman spectroscopy, atomic force microscopy, and transmission electron microscopy to investigate nanomaterials irradiated by a 23 MeV I beam. We found a significant influence of the ion charge state on damage production in monolayer graphene, but found no evidence of this effect in bilayer and trilayer graphene, nor in graphite. Furthermore, we found no evidence of this effect in CaF2 and SiO2 nanocrystals irradiated with the same ion beam. Full article
(This article belongs to the Special Issue 2D Crystalline Nanomaterials)
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Figure 1
<p>(<b>a</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and charge state <span class="html-italic">Q =</span> 6+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>b</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and equilibrium charge state <span class="html-italic">Q =</span> 14+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>c</b>) Comparison of Raman spectra for monolayer graphene irradiated with 23 MeV I beam at the fluence of 5 × 10<sup>12</sup> ions/cm<sup>2</sup> with the charge state of <span class="html-italic">Q =</span> 6+ and <span class="html-italic">Q =</span> 14+. (<b>d</b>) Ratio of the peak intensities I<sub>D</sub>/I<sub>G</sub> as a function of the applied ion fluence and charge state <span class="html-italic">Q</span> for monolayer graphene (blue), bilayer graphene (green), trilayer graphene (orange), and HOPG (black).</p> Full article ">Figure 1 Cont.
<p>(<b>a</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and charge state <span class="html-italic">Q =</span> 6+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>b</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and equilibrium charge state <span class="html-italic">Q =</span> 14+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>c</b>) Comparison of Raman spectra for monolayer graphene irradiated with 23 MeV I beam at the fluence of 5 × 10<sup>12</sup> ions/cm<sup>2</sup> with the charge state of <span class="html-italic">Q =</span> 6+ and <span class="html-italic">Q =</span> 14+. (<b>d</b>) Ratio of the peak intensities I<sub>D</sub>/I<sub>G</sub> as a function of the applied ion fluence and charge state <span class="html-italic">Q</span> for monolayer graphene (blue), bilayer graphene (green), trilayer graphene (orange), and HOPG (black).</p> Full article ">Figure 1 Cont.
<p>(<b>a</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and charge state <span class="html-italic">Q =</span> 6+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>b</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and equilibrium charge state <span class="html-italic">Q =</span> 14+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>c</b>) Comparison of Raman spectra for monolayer graphene irradiated with 23 MeV I beam at the fluence of 5 × 10<sup>12</sup> ions/cm<sup>2</sup> with the charge state of <span class="html-italic">Q =</span> 6+ and <span class="html-italic">Q =</span> 14+. (<b>d</b>) Ratio of the peak intensities I<sub>D</sub>/I<sub>G</sub> as a function of the applied ion fluence and charge state <span class="html-italic">Q</span> for monolayer graphene (blue), bilayer graphene (green), trilayer graphene (orange), and HOPG (black).</p> Full article ">Figure 1 Cont.
<p>(<b>a</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and charge state <span class="html-italic">Q =</span> 6+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>b</b>) Raman spectra of the monolayer graphene irradiated with 23 MeV iodine beam and equilibrium charge state <span class="html-italic">Q =</span> 14+, with fluences between 5 × 10<sup>12</sup> and 5 × 10<sup>13</sup> ions/cm<sup>2</sup>. For comparison, a spectrum from unirradiated graphene is also added. (<b>c</b>) Comparison of Raman spectra for monolayer graphene irradiated with 23 MeV I beam at the fluence of 5 × 10<sup>12</sup> ions/cm<sup>2</sup> with the charge state of <span class="html-italic">Q =</span> 6+ and <span class="html-italic">Q =</span> 14+. (<b>d</b>) Ratio of the peak intensities I<sub>D</sub>/I<sub>G</sub> as a function of the applied ion fluence and charge state <span class="html-italic">Q</span> for monolayer graphene (blue), bilayer graphene (green), trilayer graphene (orange), and HOPG (black).</p> Full article ">Figure 2
<p>(<b>a</b>) AFM images of the graphene surface before irradiation, (<b>b</b>) after irradiation with a charge state of <span class="html-italic">Q =</span> 6+ and (<b>c</b>) after irradiation with equilibrium charge state, both with the same 5 × 10<sup>13</sup> ions/cm<sup>2</sup> fluence. The images have the same false colour vertical scale range of 3 nm.</p> Full article ">Figure 2 Cont.
<p>(<b>a</b>) AFM images of the graphene surface before irradiation, (<b>b</b>) after irradiation with a charge state of <span class="html-italic">Q =</span> 6+ and (<b>c</b>) after irradiation with equilibrium charge state, both with the same 5 × 10<sup>13</sup> ions/cm<sup>2</sup> fluence. The images have the same false colour vertical scale range of 3 nm.</p> Full article ">Figure 3
<p>TEM image (<b>a</b>) and corresponding SAED pattern (<b>b</b>) revealing the FCC structure of the unirradiated CaF<sub>2</sub> nanocrystals. Under-focused (<b>c</b>) and over-focused (<b>d</b>) TEM images of the CaF<sub>2</sub> nanocrystals irradiated with 23 MeV I at the fluence of 1 × 10<sup>11</sup> ions/cm<sup>2</sup> with charge state of <span class="html-italic">Q =</span> 6+. Under-focused (<b>e</b>) and over-focused (<b>f</b>) TEM images of the CaF<sub>2</sub> nanocrystals irradiated with 23 MeV I at the fluence of 1 × 10<sup>11</sup> ions/cm<sup>2</sup> with the equilibrated charge state.</p> Full article ">Figure 4
<p>TEM image (<b>a</b>) and corresponding SAED pattern (<b>b</b>) revealing the hexagonal structure of the unirradiated SiO<sub>2</sub> nanocrystals. Over-focused TEM image (<b>c</b>) of the SiO<sub>2</sub> nanocrystals irradiated with 23 MeV I at the fluence of 1 × 10<sup>11</sup> ions/cm<sup>2</sup> with charge state of <span class="html-italic">Q =</span> 6+. Over-focused TEM image (<b>d</b>) of the SiO<sub>2</sub> nanocrystals irradiated with 23 MeV I at the fluence of 1 × 10<sup>11</sup> ions/cm<sup>2</sup> with the equilibrated charge state. Ion tracks in SiO<sub>2</sub> pointed by arrows in (<b>e</b>) fade away and disappear after prolonged exposure to the electron beam (<b>f</b>).</p> Full article ">Figure 5
<p>Distribution of the ion track diameters in CaF<sub>2</sub> nanocrystals irradiated with 23 MeV I at the fluence of 1 × 10<sup>11</sup> ions/cm<sup>2</sup> with (<b>a</b>) equilibrated charge state and (<b>b</b>) charge state of <span class="html-italic">Q =</span> 6+. Distribution of the ion track diameters in SiO<sub>2</sub> nanocrystals irradiated with 23 MeV I at the fluence of 1 × 10<sup>11</sup> ions/cm<sup>2</sup> with (<b>c</b>) equilibrated charge state and (<b>d</b>) charge state of <span class="html-italic">Q =</span> 6+.</p> Full article ">
10 pages, 4172 KiB  
Article
Properties of Self-Compacting Concrete Using Multi-Component Blend Binders for CO2 Reduction
by Yong Jic Kim
Crystals 2022, 12(6), 864; https://doi.org/10.3390/cryst12060864 - 19 Jun 2022
Viewed by 1527
Abstract
This paper aims to reduce the quantity of cement used by up to 80% by utilizing industrial by-products. By reducing the amount of cement used, there is an effect of reducing CO2 emissions during cement manufacturing. To reduce the amount of cement [...] Read more.
This paper aims to reduce the quantity of cement used by up to 80% by utilizing industrial by-products. By reducing the amount of cement used, there is an effect of reducing CO2 emissions during cement manufacturing. To reduce the amount of cement used, ground granulated blast-furnace slag (GGBF), fly-ash (FA), and calcium carbonate (CC) were used as substitute materials for cement. CC is a by-product, discharged by collecting CO2 emitted from a coal-fired power plant and reacting with additives. The specific surface area and the average particle size of CC used are 12,239 cm2/g and 5.9 μm (D50), respectively. The viscosity of pastes that contained GGFF and FA decreased by up to 51 and 49% respectively compared to the use of only cement (OPC) paste. However, paste using with CC increased up to 23% in relation to plain. As a result of measuring slump flow, segregation resistance ability, and filling ability to evaluate construction performance, slump flow was reduced by up to 3% (G40F10C30) in relation to plain concrete. Segregation resistance ability of fresh concrete using, GGBF (15, 30, and 45%), FA (10, 20, and 30%), CC (10, 20, and 30%), the time it takes for the slump flow to reach 500 mm, time it takes to through the V-funnel showed a decreasing tendency as the usage of FA increased. However, CC increased with increasing mixing ratio. This trend is, the viscosity increase when CC was mixed in terms of rheology. Filling ability of fresh concrete using GGBF (15, 30, and 45%), FA (10, 20, and 30%) and CC (10, 20, and 30%), the criteria were met, and the average increase was 16% and the maximum was 20% in relation to plain concrete. In the case of compressive strength, the compressive strength at 1 day was found to be an average of 5 MPa when 80% of the cementitious was substituted. At 3 days, at least 8 MPa was measured. The compressive strength at 28 days showed a tendency to decrease as the mixing rate of CC increased, but was measured to be at least 34 MPa. The relationship between compressive strength and splitting tensile strength or elastic modulus at 28 days satisfies the standard range. Full article
(This article belongs to the Special Issue Crystalizations in Cementitous Composites)
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<p>Self-compacting concrete properties evaluation equipment.</p> Full article ">Figure 2
<p>Particle size distribution of CC.</p> Full article ">Figure 3
<p>SEM image of CC.</p> Full article ">Figure 4
<p>X-ray diffraction analysis of CC.</p> Full article ">Figure 5
<p>Shear rate and shear stress of paste.</p> Full article ">Figure 6
<p>Results of air content.</p> Full article ">Figure 7
<p>Results of slump flow.</p> Full article ">Figure 8
<p>Time it takes to through the V-funnel and the time it takes for the slump flow to reach 500 mm.</p> Full article ">Figure 9
<p>U-box test.</p> Full article ">Figure 10
<p>Compressive strength.</p> Full article ">Figure 11
<p>Compressive and splitting tensile strength.</p> Full article ">Figure 12
<p>Compressive strength and elastic moduli.</p> Full article ">
12 pages, 8561 KiB  
Article
Stable CsPbBr3 Nanocrystals—Decorated Nanoporous Gold for Optoelectronic Applications
by Jessica Satta, Andrea Pinna, Giorgio Pia, Luca Pilia, Carlo Maria Carbonaro, Daniele Chiriu, Luigi Stagi, Qader Abdulqader Abdullah and Pier Carlo Ricci
Crystals 2022, 12(6), 863; https://doi.org/10.3390/cryst12060863 - 18 Jun 2022
Cited by 2 | Viewed by 2375
Abstract
Halide perovskite colloidal nanocrystals have recently gained much attention thanks to their superior stability compared with their bulk counterpart and to their unique optical properties. In this paper, two systems combining nanocrystals and nanoporous gold are studied to create an optimal metal semiconductor [...] Read more.
Halide perovskite colloidal nanocrystals have recently gained much attention thanks to their superior stability compared with their bulk counterpart and to their unique optical properties. In this paper, two systems combining nanocrystals and nanoporous gold are studied to create an optimal metal semiconductor heterojunction that can be used in photocatalysis and photovoltaic devices. The perovskite degradation phenomenon is observed when the nanoporous gold powder is mixed into the hexane suspension of nanocrystals, while the charge separation efficiency is increased by synthesizing the nanocrystals directly onto the gold porous structure. The analysis of the structural and optical properties evidences an energy transfer efficiency of 47%, along with the high structural stability of the hybrid system. Full article
(This article belongs to the Special Issue Feature Papers on "Hybrid and Composite Crystalline Materials" 2021-2022)
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Figure 1
<p>(<b>a</b>) SEM image of nanoporous Au; scale bar: 100 nm. (<b>b</b>) TEM image of CsPbBr<sub>3</sub> NCs; scale bar 200 nm; in the inset is the size distribution of CsPbBr<sub>3</sub> nanocrystals.</p> Full article ">Figure 2
<p>Rietveld refinement of the nanocrystals precipitate. Note: ■ refers to the experimental pattern, the red line is the pattern calculated via Rietveld refinement, while the black line shows the residuals between the experimental and calculated patterns.</p> Full article ">Figure 3
<p>Raman spectrum of nanocrystal precipitate; in the inset is a magnified view of the region of 200–400 cm<sup>−1</sup>. Note: λ<sub>exc</sub> = 785 nm.</p> Full article ">Figure 4
<p>Absorption (brown) and emission (green) spectra of colloidal CsPbBr<sub>3</sub> NCs; λ<sub>exc</sub> = 410 nm.</p> Full article ">Figure 5
<p>Photographs under UV light (375 nm) of the CsPbBr<sub>3</sub> NCs dispersion (<b>a</b>) before and (<b>b</b>) after the introduction of nanoporous gold.</p> Full article ">Figure 6
<p>Raman spectrum of NP Au soaked with CsPbBr<sub>3</sub> NCs (red) compared with pure CsPbBr<sub>3</sub> NCs (blue).</p> Full article ">Figure 7
<p>XRD pattern of the sample of pure NP Au (blue) and the NCs@NP Au heterostructure (red). The vertical bar individuates the main peaks of pure CsPbBr<sub>3</sub> NCs.</p> Full article ">Figure 8
<p>TEM images of NP Au (<b>a</b>) and the NC–NP Au hybrid structure (<b>b</b>).</p> Full article ">Figure 9
<p>Steady-state luminescence spectra of pure CsPbBr<sub>3</sub> NCs and the NCs–NP Au hybrid structure; λ<sub>exc</sub> = 410 nm.</p> Full article ">Figure 10
<p>Time-resolved photoluminescence measurements of pure CsPbBr<sub>3</sub> NCs and the NCs–NP Au hybrid structure; λ<sub>exc</sub> = 410 nm.</p> Full article ">
18 pages, 5181 KiB  
Article
Fabrication of Copper(II)-Coated Magnetic Core-Shell Nanoparticles Fe3O4@SiO2: An Effective and Recoverable Catalyst for Reduction/Degradation of Environmental Pollutants
by Jaber Dadashi, Mohammad Khaleghian, Babak Mirtamizdoust, Younes Hanifehpour and Sang Woo Joo
Crystals 2022, 12(6), 862; https://doi.org/10.3390/cryst12060862 - 18 Jun 2022
Cited by 11 | Viewed by 2812
Abstract
In this work, we report the synthesis of a magnetically recoverable catalyst through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L–Cu(II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined [...] Read more.
In this work, we report the synthesis of a magnetically recoverable catalyst through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L–Cu(II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined and characterized by energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM), and thermogravimetric-differential thermal analysis (TG-DTA) procedures. The [Fe3O4@SiO2-L–Cu(II)] was used for the reduction of Cr(VI), 4-nitrophenol (4-NP) and organic dyes such as Congo Red (CR) and methylene blue (MB) in aqueous media. Catalytic performance studies showed that the [Fe3O4@SiO2–L–Cu(II)] has excellent activity toward reduction reactions under mild conditions. Remarkable attributes of this method are high efficiency, removal of a homogeneous catalyst, easy recovery from the reaction mixture, and uncomplicated route. The amount of activity in this catalytic system was almost constant after several stages of recovery and reuse. The results show that the catalyst was easily separated and retained 83% of its efficiency after five cycles without considerable loss of activity and stability. Full article
(This article belongs to the Special Issue Nanocrystalline Materials: Preparation, Structural, Magnetic, Dielectric, Electrical, Optical, Thermal Properties and Applications (Volume II))
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Graphical abstract

Graphical abstract
Full article ">Figure 1
<p>The FT-IR spectra of the [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)] complex.</p> Full article ">Figure 2
<p>X-ray diffraction pattern of [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)].</p> Full article ">Figure 3
<p>The magnetization curve for the magnetic nanocatalyst.</p> Full article ">Figure 4
<p>Energy dispersive X-ray spectrum of the [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)].</p> Full article ">Figure 5
<p>(<b>a</b>) and (<b>b</b>) Field emission scanning electron microscopy images of the [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)] at different magnification.</p> Full article ">Figure 6
<p>The thermogravimetric-differential thermal analysis data was determined for the magnetic nano-catalyst.</p> Full article ">Figure 7
<p>The concentration change of 4-nitrophenol over the reaction time.</p> Full article ">Figure 8
<p>The UV-visible spectrum of the 4-nitrophenol reduced with NaBH<sub>4</sub> in [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)]. A: 4-NP, B: 4-nitrophenolate ion, C: 4-AP. Different colored lines created by various time of reaction from zero to 114 s.</p> Full article ">Figure 9
<p>The concentration change of Cr(VI) over the reaction time.</p> Full article ">Figure 10
<p>The Cr(VI) aqueous solution’s UV-Vis spectra were utilizing HCOOH (1.0 mL) and [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)]. Different colored line created by various time of reaction from zero to 11 min.</p> Full article ">Figure 11
<p>The UV-visible spectrum of the methylene blue degraded by NaBH<sub>4</sub> in [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)] at different time of reaction.</p> Full article ">Figure 12
<p>The UV-visible spectrum of the degraded Congo Red by NaBH<sub>4</sub> in [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)].</p> Full article ">Figure 13
<p>Magnetic removal and recoverability of nanocatalyst for 4-NP reduction at room temperature.</p> Full article ">Figure 14
<p>Diagram of magnetic nanocatalyst after applying five times in the reaction.</p> Full article ">Scheme 1
<p>Molecular structure of L ligand.</p> Full article ">Scheme 2
<p>Preparing the [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)].</p> Full article ">Scheme 3
<p>The reduction of 4-nitrophenol to 4-aminophenol applying [Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>–L–Cu(II)].</p> Full article ">Scheme 4
<p>The schematic reduction of Cr(VI) to Cr(III) utilizing magnetic nanocatalyst.</p> Full article ">Scheme 5
<p>The schematic degradation of methylene blue and Congo Red utilizing magnetic nano-catalyst.</p> Full article ">
11 pages, 7157 KiB  
Article
X-ray Structure Analyses and Biological Evaluations of a New Cd(II) Complex with S-Triazine Based Ligand
by Kholood A. Dahlous, Atallh A. M. Alotaibi, Necmi Dege, Ayman El-Faham, Saied M. Soliman and Heba M. Refaat
Crystals 2022, 12(6), 861; https://doi.org/10.3390/cryst12060861 - 18 Jun 2022
Cited by 7 | Viewed by 1950
Abstract
The crystal structure of a new penta-coordinated Cd(II) complex of the formula [Cd(BPMT)Br2] was presented. This Cd(II) complex was synthesized by mixing Cd(NO3)2·4H2O and 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (BPMT) in the presence [...] Read more.
The crystal structure of a new penta-coordinated Cd(II) complex of the formula [Cd(BPMT)Br2] was presented. This Cd(II) complex was synthesized by mixing Cd(NO3)2·4H2O and 2,4-bis(3,5-dimethyl-1H-pyrazol-1-yl)-6-methoxy-1,3,5-triazine (BPMT) in the presence of KBr. It crystallized in the monoclinic crystal system and P21/n space group. The crystal parameters are a = 11.3680(8) Å, b = 11.1648(8) Å, c = 15.8593(11) Å, and β = 103.563(2)°, while the unit cell volume is 2190.6(12) Å3 and it comprised four molecules. The supramolecular structure of the [Cd(BPMT)Br2] complex is mainly controlled by the intermolecular Br∙∙∙H interactions. Hirshfeld calculations predicted the H∙∙∙H (38.1%), Br∙∙∙H (24.3%), C∙∙∙H (11.1%), and N∙∙∙H (9.5%) interactions are the most dominant. Biological evaluations for the antimicrobial and anticancer properties of the studied complex are presented. The Cd(II) complex has better anticancer and antibacterial activities than the free BPMT ligand. The anticancer activity against lung carcinoma (A-549) is higher for the former (18.64 ± 1.09 µg/mL) compared to the latter (372.79 ± 13.64 µg/mL). Additionally, the best antibacterial activity for the Cd(II) complex was found against B. subtilis. Full article
(This article belongs to the Special Issue New Trends in Crystals at Saudi Arabia (Volume II))
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<p>Structure of the <b>BPMT</b> ligand.</p> Full article ">Figure 2
<p>X-ray structure of [Cd(<b>BPMT</b>)Br<sub>2</sub>].</p> Full article ">Figure 3
<p>Important contacts (<b>A</b>) and packing scheme (<b>B</b>) in the [Cd(BPMT)Br<sub>2</sub>] complex.</p> Full article ">Figure 4
<p>Percentages of all intermolecular contacts in the [Cd(BPMT)Br<sub>2</sub>] complex.</p> Full article ">Figure 5
<p>Hirshfeld surfaces of the [Cd(BPMT)Br<sub>2</sub>] complex. The shape index and curvedness maps revealed the absence of aromatic π-π stacking interactions.</p> Full article ">Figure 6
<p>The decomposed fingerprint of the important interactions in the [Cd(BPMT)Br<sub>2</sub>] complex.</p> Full article ">Figure 7
<p>Cytotoxic activity of the [Cd(BPMT)Br<sub>2</sub>] complex against lung cancer cells (A-549). The detailed results are tabulated in <a href="#app1-crystals-12-00861" class="html-app">Tables S1 and S2</a>.</p> Full article ">Scheme 1
<p>Synthesis of [Cd(BPMT)Br<sub>2</sub>].</p> Full article ">
14 pages, 4945 KiB  
Article
Structural, Thermal and Functional Properties of a Hybrid Dicyanamide-Perovskite Solid Solution
by Javier García-Ben, Jorge Salgado-Beceiro, Ignacio Delgado-Ferreiro, Pedro Dafonte-Rodríguez, Jorge López-Beceiro, Ramón Artiaga, Socorro Castro-García, Manuel Sánchez-Andújar, Juan Manuel Bermúdez-García and María Antonia Señarís-Rodríguez
Crystals 2022, 12(6), 860; https://doi.org/10.3390/cryst12060860 - 18 Jun 2022
Cited by 1 | Viewed by 1817
Abstract
In Solid-State Chemistry, a well-known route to obtain new compounds and modulate their properties is the formation of solid solutions, a strategy widely exploited in the case of classical inorganic perovskites but relatively unexplored among emergent hybrid organic–inorganic perovskites (HOIPs). In this work, [...] Read more.
In Solid-State Chemistry, a well-known route to obtain new compounds and modulate their properties is the formation of solid solutions, a strategy widely exploited in the case of classical inorganic perovskites but relatively unexplored among emergent hybrid organic–inorganic perovskites (HOIPs). In this work, to the best of our knowledge, we present the first dicyanamide-perovskite solid solution of [TPrA][Co0.5Ni0.5(dca)3] and study its thermal, dielectric and optical properties, comparing them with those of the parent undoped compounds [TPrA][Co(dca)3] and [TPrA][Ni(dca)3]. In addition, we show that the prepared doped compound can be used as a precursor that, by calcination, allows CNTs with embedded magnetic Ni:Co alloy nanoparticles to be obtained through a fast and much simpler synthetic route than other complex CVD or arc-discharge methods used to obtain this type of material. Full article
(This article belongs to the Special Issue Solid State Chemistry: Memorial Issue for Professor Emilio Morán)
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<p>Cubic single crystals of [TPrA][Co<sub>x</sub>Ni<sub>1</sub><sub>−</sub><sub>x</sub>(dca)<sub>3</sub>], where x = 1.0, 0.5 and 0.0.</p> Full article ">Figure 2
<p>(<b>a</b>) Powder X-ray diffraction patterns of [TPrA][Co<sub>x</sub>Ni<sub>1</sub><sub>−</sub><sub>x</sub>(dca)<sub>3</sub>], where x = 1.5, 0.5 and 0.0. (<b>b</b>) Details of a region of (<b>a</b>) to show the shape and the shift of the peak as x changes.</p> Full article ">Figure 3
<p>(<b>a</b>) Lattice parameters and (<b>b</b>) unit cell volume for [TPrA][Co<sub>x</sub>Ni<sub>(1</sub><sub>−</sub><sub>x)</sub>(dca)<sub>3</sub>], where x = 1.0, 0.5 and 0.0.</p> Full article ">Figure 4
<p>A polyhedral/ball-and-stick representation of the crystal structure of [TPrA][Co<sub>0.5</sub>Ni<sub>0.5</sub>(dca)<sub>3</sub>] polymorph I (T = 100 K) along the <span class="html-italic">b</span>-axis.</p> Full article ">Figure 5
<p>DSC curve of [TPrA][Co<sub>0.5</sub>Ni<sub>0.5</sub>(dca)<sub>3</sub>] from 200 K to 360 K and comparison with the reported data for [TPrA][Co(dca)<sub>3</sub>] and [TPrA][Ni(dca)<sub>3</sub>] (data obtained from Reference [<a href="#B24-crystals-12-00860" class="html-bibr">24</a>]).</p> Full article ">Figure 6
<p>TGA curves of [TPrA][Co<sub>x</sub>Ni<sub>1</sub><sub>−</sub><sub>x</sub>(dca)<sub>3</sub>], where x = 1.0, 0.5 and 0.0, from 300 K to 1200 K.</p> Full article ">Figure 7
<p>(<b>a</b>) Dielectric constant of the [TPrA][Co<sub>0.5</sub>Ni<sub>0.5</sub>(dca)<sub>3</sub>] material during heating from 148 K to 390 K. (<b>b</b>) Dielectric constant comparison between [TPrA][Co<sub>x</sub>Ni<sub>1</sub><sub>−</sub><sub>x</sub>(dca)<sub>3</sub>], where x = 1.0, 0.5 and 0.0.</p> Full article ">Figure 8
<p>UV-Vis spectra of [TPrA][Co<sub>x</sub>Ni<sub>1</sub><sub>−</sub><sub>x</sub>(dca)<sub>3</sub>], where x = 1.0, 0.5 and 0.0, between 200 and 900 nm.</p> Full article ">Figure 9
<p>(<b>a</b>) Powder X-ray diffraction patterns obtained after the calcination of [TPrA][Co<sub>x</sub>Ni<sub>1</sub><sub>−</sub><sub>x</sub>(dca)<sub>3</sub>] where x = 1.0, 0.5, 0.0. (<b>b</b>) Detail in the region of the maximum intensity peak.</p> Full article ">Figure 10
<p>(<b>a</b>) SEM and (<b>b</b>) TEM images of the product obtained by the calcination of the [TPrA][Co<sub>0.5</sub>Ni<sub>0.5</sub>(dca)<sub>3</sub>] precursor.</p> Full article ">
13 pages, 4515 KiB  
Article
Factors Influencing Recognition Capability of Inverse Opal Structured Photonic Crystal Sensors
by Chaokun Yang, Mengyao Pan and Xin Zhao
Crystals 2022, 12(6), 859; https://doi.org/10.3390/cryst12060859 - 17 Jun 2022
Viewed by 1455
Abstract
Nowadays, many kinds of colloidal photonic crystal (PC) sensors with inverse opal (IO) structures have been developed. However, there are few systematic studies on the factors influencing their recognition capability and responsiveness capability. In this paper, the relationships between recognition capability of IO [...] Read more.
Nowadays, many kinds of colloidal photonic crystal (PC) sensors with inverse opal (IO) structures have been developed. However, there are few systematic studies on the factors influencing their recognition capability and responsiveness capability. In this paper, the relationships between recognition capability of IO structured PC sensors and all the parameters in Bragg–Snell’s law have been explored. In addition, research on the recognition ability of PC sensors typically focuses only on the refractive index difference between the identified substances. Herein, we define two concepts, namely the absolute refractive index difference and the relative refractive index difference, and prove that the recognition ability not only relies on the absolute refractive index between the identified substances, but also on the relative refractive index. Bragg–Snell’s law analysis confirms that the responsiveness capability is directly proportional to the void size of the IO structure, which is also confirmed by the finite difference time domain (FDTD) method. It is believed that these systematic studies have important guiding significance for creating advanced IO structured PC sensors. Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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<p>Relationship between central reflection wavelength (<span class="html-italic">λ</span><sub>IO</sub>) of the IO structure (<span class="html-italic">λ</span><sub>IO</sub>) based on Ge matrix and void sizes (<span class="html-italic">D</span><sub>void</sub>) of the system.</p> Full article ">Figure 2
<p>The relationships between the wavelength range contrast (Δ<span class="html-italic">λ</span><sub>contrast</sub>) and relative difference of refractive indices (Δ<span class="html-italic">n</span><sub>s-r</sub>).</p> Full article ">Figure 3
<p>The relationship between the wavelength range contrast (Δ<span class="html-italic">λ</span><sub>contrast</sub>) and the relative difference of refractive index between external Substance 1 and Substance 2 (Δ<span class="html-italic">n</span><sub>s-r</sub>).</p> Full article ">Figure 4
<p>Typical examples of wavelength response range (Δ<span class="html-italic">λ</span><sub>PEGDA</sub>) of the PC sensor as a function of void ratio (<span class="html-italic">ϕ</span>) and void diameter (<span class="html-italic">D</span>).</p> Full article ">Figure 5
<p>The relationship between wavelength range contrast (Δ<span class="html-italic">λ</span><sub>PEGDA-contrast</sub>) and void ratio (<span class="html-italic">D</span>) of the system.</p> Full article ">Figure 6
<p>Simulation results of reflection spectra of IO structure containing PEGDA matrix and voids with diameters of (<b>a</b>) 130 nm; (<b>b</b>) 150 nm; (<b>c</b>) 180 nm; (<b>d</b>) 200 nm; and (<b>e</b>) 220 nm.</p> Full article ">Figure 7
<p>Simulation results of reflection spectra of IO structure containing PEGDA matrix and voids after response to water, where the void sizes in the system are (<b>a</b>) 130 nm; (<b>b</b>) 150 nm; (<b>c</b>) 180 nm; (<b>d</b>) 200 nm; and (<b>e</b>) 220 nm.</p> Full article ">Figure 8
<p>The relationship between wavelength response range and void sizes predicted by Bragg–Snell’s law and calculated by FDTD method.</p> Full article ">Figure 9
<p>Simulation results of reflection spectra of IO structure systems after response to water, where the matrix materials of the systems are (<b>a</b>) WO<sub>3</sub>, (<b>b</b>) SnO<sub>2</sub> and (<b>c</b>) TiO<sub>2</sub>.</p> Full article ">Figure 10
<p>Simulation results of reflection spectra of IO structure composed of PGEDA matrix and void arrays with (<b>a</b>) 6 layers and (<b>b</b>) 12 layers before and after response to water.</p> Full article ">
23 pages, 22661 KiB  
Review
Review of Additive Manufacturing Techniques for Large-Scale Metal Functionally Graded Materials
by Ruiying Zhang, Fan Jiang, Long Xue and Junyu Yu
Crystals 2022, 12(6), 858; https://doi.org/10.3390/cryst12060858 - 17 Jun 2022
Cited by 12 | Viewed by 4092
Abstract
Functionally graded materials (FGMs), which constitute a new type of composite material, have received considerable attention in industry because of the spatial gradient of their composition and the microstructure-induced gradient in their material performance, which make them better suited for high-performance multifunctional applications. [...] Read more.
Functionally graded materials (FGMs), which constitute a new type of composite material, have received considerable attention in industry because of the spatial gradient of their composition and the microstructure-induced gradient in their material performance, which make them better suited for high-performance multifunctional applications. Additive manufacturing (AM) has become one of the most promising techniques for the manufacture of materials and structures because of its high flexibility. The combination of advanced materials (FGMs) and advanced manufacturing methods (AM) is expected to facilitate the further development of such engineering materials. In this paper, the definition, historical development and material gradient types of FGMs are introduced. The classification, process principle and typical research results of the AM of metal FGMs are summarized and discussed. In particular, the research status of wire and arc additive manufacture (WAAM), which is more suitable for the preparation of large-scale metal FGMs, is reviewed in detail according to the types of FGMs, and a double-wire bypass plasma arc additive manufacturing technique, which is suitable for inducing a gradient along the direction of single-pass cladding, is proposed. On the basis of this summary of the important achievements made to date, future research is proposed. Full article
(This article belongs to the Special Issue Physical Mechanism of Welding of Metallic Materials)
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<p>Various types of gradients in FGMs [<a href="#B5-crystals-12-00858" class="html-bibr">5</a>].</p> Full article ">Figure 2
<p>Schematic illustration of additively manufactured gradient metallic materials [<a href="#B2-crystals-12-00858" class="html-bibr">2</a>,<a href="#B38-crystals-12-00858" class="html-bibr">38</a>].</p> Full article ">Figure 3
<p>Schematic of the DED process [<a href="#B45-crystals-12-00858" class="html-bibr">45</a>].</p> Full article ">Figure 4
<p>(<b>a</b>) Photographic image of the LENS<sup>TM</sup> process, (<b>b</b>) Schematic of the FGMs Inconel 718/SS 316L, (<b>c</b>) EBSD micrographs of the FGM in the defective compositional range of 30 wt.% Inconel 718/70 wt.% SS 316L to 20 wt.% Inconel 718/80 wt.% SS 316L [<a href="#B50-crystals-12-00858" class="html-bibr">50</a>].</p> Full article ">Figure 5
<p>(<b>a</b>–<b>e</b>) IPF figures of MSS/ASS FGMs for region with different mass fractions [<a href="#B47-crystals-12-00858" class="html-bibr">47</a>].</p> Full article ">Figure 6
<p>The cross-section of SS316L/IN718 samples under different gradient types fabricated by DLMD: (<b>a</b>) Composition changed every two layers, (<b>b</b>) Composition changed every one layer [<a href="#B52-crystals-12-00858" class="html-bibr">52</a>].</p> Full article ">Figure 7
<p>Schematic of LPBF [<a href="#B55-crystals-12-00858" class="html-bibr">55</a>]. (<b>a</b>) Overview of SEM micrograph for monolithic H13 (<b>b</b>) high-magnification image of the dashed square shown in (<b>a</b>), (<b>c</b>) Overview of SEM micrograph for 1wt.%VC-H13, (<b>d</b>) high-magnification image of the dashed square shown in (<b>c</b>), (<b>e</b>) Overview of SEM micrograph for 3wt.%VC-H13, (<b>f</b>) high-magnification image of the dashed square shown in (<b>e</b>) [<a href="#B55-crystals-12-00858" class="html-bibr">55</a>].</p> Full article ">Figure 8
<p>(<b>a</b>) Schematic of the SLM, (<b>b</b>) Design of the powder feeder system, (<b>c</b>) Schematic of the powder feeder for mixing powders, (<b>d</b>–<b>g</b>) Sample and the cross-sections of different layers of FGMs with pure Fe/Al-12Si [<a href="#B58-crystals-12-00858" class="html-bibr">58</a>].</p> Full article ">Figure 9
<p>(<b>a</b>) Schematic of employing two different laser sources within one sample to obtain FGMs, (<b>b</b>) Microstructure analyses for FGMs [<a href="#B56-crystals-12-00858" class="html-bibr">56</a>].</p> Full article ">Figure 10
<p>(<b>a</b>) Schematic of the secondary feeder in EB-PBF, (<b>b</b>) Schematic of Mo–Mo + TiC–Mo sandwich sample [<a href="#B64-crystals-12-00858" class="html-bibr">64</a>].</p> Full article ">Figure 11
<p>Schematic of the fabrication of FGMs by EBSM and the microstructure for different zones [<a href="#B36-crystals-12-00858" class="html-bibr">36</a>].</p> Full article ">Figure 12
<p>Schematic of the fabrication of FGMs by EBWAM: (<b>a</b>) SS wire deposition, (<b>b</b>) Copper wire deposition, (<b>c</b>) Microstructural scheme of the evolution of microstructure for the gradient zone [<a href="#B66-crystals-12-00858" class="html-bibr">66</a>].</p> Full article ">Figure 13
<p>(<b>a</b>) Schematic of the GTA-AM system [<a href="#B69-crystals-12-00858" class="html-bibr">69</a>], (<b>b</b>) Microstructure of the cladding layer with different nitrogen flow rates [<a href="#B69-crystals-12-00858" class="html-bibr">69</a>], (<b>c</b>) XRD patterns of base material and individual layers [<a href="#B70-crystals-12-00858" class="html-bibr">70</a>].</p> Full article ">Figure 14
<p>(<b>a</b>) Schematic of WAAM system, (<b>b</b>) Macrostructure of the cross section of FGMs [<a href="#B71-crystals-12-00858" class="html-bibr">71</a>].</p> Full article ">Figure 15
<p>(<b>a</b>) Schematic of WAAM system, (<b>b</b>) Schematic of double-wire-feeding units [<a href="#B72-crystals-12-00858" class="html-bibr">72</a>].</p> Full article ">Figure 16
<p>Microstructure with progressively higher Al content from the bottom to the top [<a href="#B72-crystals-12-00858" class="html-bibr">72</a>].</p> Full article ">Figure 17
<p>Schematic of WLAAM [<a href="#B77-crystals-12-00858" class="html-bibr">77</a>].</p> Full article ">Figure 18
<p>(<b>a</b>) Schematic of WAAM system, (<b>b</b>) Deposition path patterns [<a href="#B82-crystals-12-00858" class="html-bibr">82</a>].</p> Full article ">Figure 19
<p>(<b>a</b>) Schematic of WAAM system, (<b>b</b>) Schematic of FGMs, (<b>c</b>) FGM sample [<a href="#B84-crystals-12-00858" class="html-bibr">84</a>].</p> Full article ">Figure 20
<p>(<b>a</b>) Schematic of WAAM system based on CMT, (<b>b</b>) Front view of FGM sample, (<b>c</b>) Microstructure at locations A, B and C in figure (<b>b</b>) [<a href="#B86-crystals-12-00858" class="html-bibr">86</a>].</p> Full article ">Figure 21
<p>(<b>a</b>) Schematic of WAAM based on bypass-PA [<a href="#B87-crystals-12-00858" class="html-bibr">87</a>], (<b>b</b>) T-section structure of AM [<a href="#B88-crystals-12-00858" class="html-bibr">88</a>].</p> Full article ">Figure 22
<p>(<b>a</b>) Schematic of WAAM based on CMT with heterogeneous wires, (<b>b</b>) Schematic of FGMs [<a href="#B90-crystals-12-00858" class="html-bibr">90</a>].</p> Full article ">Figure 23
<p>Schematic of FGMs by PA-AM [<a href="#B92-crystals-12-00858" class="html-bibr">92</a>].</p> Full article ">Figure 24
<p>(<b>a</b>) Schematic for the distribution of layers, (<b>b</b>) Cross section and microstructure of layer structure [<a href="#B93-crystals-12-00858" class="html-bibr">93</a>].</p> Full article ">Figure 25
<p>Schematic of double-wire bypass plasma arc AM.</p> Full article ">
12 pages, 9527 KiB  
Article
The Effect of Doping High Volume Magnesium Sulfate on Properties of Magnesium Oxychloride Cement
by Qing Huang, Weixin Zheng, Ying Li, Chenggong Chang, Jing Wen, Jinmei Dong and Xueying Xiao
Crystals 2022, 12(6), 857; https://doi.org/10.3390/cryst12060857 - 17 Jun 2022
Cited by 5 | Viewed by 1798
Abstract
The composite gelling system of chlorine and magnesium thioxide was prepared by mixing different mass fractions of magnesium sulfate solution into MOC. Detailed studies regarding the influences of magnesium sulfate replacing magnesium chloride on the setting time, compressive strength, and water resistance of [...] Read more.
The composite gelling system of chlorine and magnesium thioxide was prepared by mixing different mass fractions of magnesium sulfate solution into MOC. Detailed studies regarding the influences of magnesium sulfate replacing magnesium chloride on the setting time, compressive strength, and water resistance of magnesium oxychloride cement (MOC) have been carried out in this paper. The phase composition and micro morphology of the hydration products in the mixed system were analyzed by XRD and SEM. The results show that the addition of magnesium sulfate prolongs the setting time and reduces the compressive strength of the mixed MOC. Compared with the primordial MOC system, the water resistance of the mixed system improved, with the mixed system exhibiting optimal water resistance when the mass fraction of magnesium sulfate was 30%. The phases of the mixed system were composed of 5Mg(OH)2·MgCl2·8H2O and 5Mg(OH)2·MgSO4·7H2O phases. The microscopic morphology shows that the interior of air-cured MOC was composed of a large number of needle-like crystals, and continuous crystal structures have close contact and a strong bonding force. Cracks and pores appear on the surface after submerging in water, and the crystallization state of the internal crystals becomes worse. The compressive strength and water stability of MOC were closely related to the crystal morphology. Full article
(This article belongs to the Special Issue Advances in Cement-Based and Construction Materials)
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<p>The setting time of MOC at different mass fractions of MgSO4 (<b>a</b>): 6:1:15; (<b>b</b>): 7:1:18.</p> Full article ">Figure 2
<p>The compressive strength of MOC with different mass fractions of MgSO<sub>4</sub> at air curing (<b>a</b>): 6:1:15; (<b>b</b>): 7:1:18.</p> Full article ">Figure 3
<p>The compressive strength of MOC with different mass fractions of MgSO<sub>4</sub> after water immersion (<b>a</b>): 6:1:15; (<b>b</b>): 7:1:18.</p> Full article ">Figure 4
<p>The softening coefficient of cement with different mass fractions of MgSO<sub>4</sub> (<b>a</b>): 6:1:15; (<b>b</b>): 7:1:18.</p> Full article ">Figure 5
<p>The XRD patterns of cement with different mass fractions of MgSO<sub>4</sub> (<b>a</b>): Air curing for 28 days; (<b>b</b>): Water immersion for 28 days.</p> Full article ">Figure 6
<p>The content of phases in cement with different mass fractions of MgSO<sub>4</sub> (<b>a</b>) Air curing for 28 days; (<b>b</b>) Water immersion for 28 days.</p> Full article ">Figure 7
<p>The SEM images of cement with different mass fractions of MgSO<sub>4</sub> after air curing for 28 days.</p> Full article ">Figure 7 Cont.
<p>The SEM images of cement with different mass fractions of MgSO<sub>4</sub> after air curing for 28 days.</p> Full article ">Figure 8
<p>The SEM images of cement with different mass fractions of MgSO<sub>4</sub> after water immersion for 28 days.</p> Full article ">Figure 8 Cont.
<p>The SEM images of cement with different mass fractions of MgSO<sub>4</sub> after water immersion for 28 days.</p> Full article ">
12 pages, 3489 KiB  
Article
Thermodynamic Characterization of a Highly Transparent Microfluidic Chip with Multiple On-Chip Temperature Control Units
by Tianhang Yang, Jinxian Wang, Sining Lv, Songjing Li and Gangyin Luo
Crystals 2022, 12(6), 856; https://doi.org/10.3390/cryst12060856 - 17 Jun 2022
Cited by 31 | Viewed by 1973
Abstract
Indium tin oxide (ITO) is a functional material with great transparency, machinability, electrical conductivity and thermo–sensitivity. Based on its excellent thermoelectric performance, we designed and fabricated a multilayer transparent microfluidic chip with multiple sets of on–chip heating, local temperature measurement and positive on–chip [...] Read more.
Indium tin oxide (ITO) is a functional material with great transparency, machinability, electrical conductivity and thermo–sensitivity. Based on its excellent thermoelectric performance, we designed and fabricated a multilayer transparent microfluidic chip with multiple sets of on–chip heating, local temperature measurement and positive on–chip cooling function units. Temperature control plays a significant role in microfluidic approaches, especially in the devices that are designed for bioengineering, chemical synthesis and disease detection. The transparency of the chip contributes to achieve the real–time observation of fluid flow and optical detection. The chip consists of a temperature control layer made with an etched ITO deposited glass, a PDMS (polydimethylsiloxane) fluid layer, a PDMS cooling and flow control layer. The performances of the ITO on–chip microheaters, ITO on–chip temperature sensors and two coolants were tested and analyzed in different working conditions. The positive on–chip heating and cooling were proved to be area-specific under a large temperature–regulating range. This PDMS–ITO–glass based chip could be applied to both temporal and spatial stable temperature–regulating principles for various purposes. Full article
(This article belongs to the Special Issue Functional Materials and Metamaterials)
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<p>Control system and supporting devices for the microfluidic chip. (<b>A</b>) Diagram of the control system; (<b>B</b>) picture of experimental setup (Subfigure: Microfluidic chip with wires and tubing in tests).</p> Full article ">Figure 2
<p>Microfluidic chip with three layers. (<b>A</b>) Design of cooling and control layer; (<b>B</b>) design of liquid reaction layer; (<b>C</b>) design of ITO temperature control layer; (<b>D</b>) relative location of 3 layers; (<b>E</b>) micrograph of transparent components; (<b>F</b>) assembled chip; (<b>G</b>) on–chip valve.</p> Full article ">Figure 3
<p>Calibration of ITO on–chip temperature sensor. (<b>A</b>) ITO resistance recorded during slow temperature-changing process above room temperature; (<b>B</b>) slow temperature-changing process above room temperature recorded by Pt100; (<b>C</b>) linear fitting result for ITO sensor calibration; (<b>D</b>) ITO resistance recorded during fast temperature–changing process below room temperature; (<b>E</b>) fast temperature-changing process below room temperature recorded by Pt100.</p> Full article ">Figure 4
<p>Heating response of ITO microheater to a target temperature read by ITO microsensor.</p> Full article ">Figure 5
<p>Temperature distribution while heating with on–chip microheater. (<b>A</b>) Heating process while sensors were set to one temperature; (<b>B</b>) heating process while sensors were set to different temperatures.</p> Full article ">Figure 6
<p>Temperature changes for natural cooling (<b>A</b>,<b>C</b>) and positive cooling with room–temperature coolant (<b>B</b>,<b>D</b>) recorded by thermal imager (<b>A</b>,<b>B</b>) and on–chip temperature sensors (<b>C</b>,<b>D</b>). Sensor 1–top, sensor 2–bottom, sensor 3–side.</p> Full article ">Figure 7
<p>Cooling a working chip with coolant flow rates at 800 (<b>A</b>), 1200 (<b>B</b>), 2000 (<b>C</b>) μL/min.</p> Full article ">Figure 8
<p>Cooling tests below room temperature recorded by thermal imager. (<b>A</b>) Beginning of slow cooling with CaCl<sub>2</sub>; (<b>B</b>) steady stage of slow cooling with CaCl<sub>2</sub>; (<b>C</b>) beginning of fast cooling with CaCl<sub>2</sub>; (<b>D</b>) steady stage of fast cooling with CaCl<sub>2</sub>.</p> Full article ">
11 pages, 18128 KiB  
Article
Achievement of Unidirectional Aluminum Tin Oxide/UV-Curable Polymer Hybrid Film via UV Nanoimprinting Lithography for Uniform Liquid Crystal Alignment
by Dong-Wook Lee, Dong-Hyun Kim, Jonghoon Won, Jin-Young Oh and Dae-Shik Seo
Crystals 2022, 12(6), 855; https://doi.org/10.3390/cryst12060855 - 17 Jun 2022
Viewed by 1846
Abstract
A uniform unidirectional nanostructure composed of aluminum tin oxide and ultraviolet (UV)-curable polymer is introduced herein. The nanostructure was produced by UV-nanoimprint lithography (UV-NIL), and the fabricated hybrid film was used as a uniform liquid crystal (LC) alignment layer. Atomic force microscopy and [...] Read more.
A uniform unidirectional nanostructure composed of aluminum tin oxide and ultraviolet (UV)-curable polymer is introduced herein. The nanostructure was produced by UV-nanoimprint lithography (UV-NIL), and the fabricated hybrid film was used as a uniform liquid crystal (LC) alignment layer. Atomic force microscopy and line profile analysis were performed to confirm a well-ordered nanostructure with 760 nm periodicity and 30 nm height. X-ray photoelectron spectroscopy analysis was also conducted to examine the chemical modifications to the hybrid film surface during UV exposure. Optical transmittance investigation of the nanopatterned hybrid film revealed its compatibility for LC device application. Stable, uniform, and homogeneous LC alignment on the hybrid film was confirmed by polarized optical microscopy observance and analysis of LC pretilt angle. The unidirectional structure on the film surface enabled uniform LC orientation along with surface anisotropy property. Hence, we expect that the proposed UV-NIL process can be applied to fabricate high-resolution unidirectional nanostructures with various inorganic/organic hybrid materials and that these nanostructures have high potential for next-generation LC systems. Full article
(This article belongs to the Special Issue Feature Articles in Liquid Crystals from Our Editorial Board Members and Their Colleagues, 2022/2023)
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<p>UV-curable polymers used in this research and their structures of chemical molecules: (<b>a</b>) 2-hydroxyethyl acrylate, (<b>b</b>) tripropylene glycol diacrylate, and (<b>c</b>) dipentaerythritol hexaacrylate.</p> Full article ">Figure 2
<p>Schematic of the unidirectional nanostructure shifting process from PDMS mold to UV-curable polymer/AlSnO hybrid film surface by UV-NIL process.</p> Full article ">Figure 3
<p>(<b>a</b>) PDMS mold and UV-nanoimprinted hybrid films 3-D (<b>left</b>), top-view (<b>middle</b>) AFM images, and corresponding line profiles (<b>right</b>) according to UV exposure time: (<b>b</b>) 1 min, (<b>c</b>) 3 min, and (<b>d</b>) 6 min.</p> Full article ">Figure 4
<p>(<b>a</b>) XPS survey-scan spectra in the range of 50 to 525 eV for the 1 min and 6 min UV-exposed hybrid films. High resolution Al 2p, Sn 3d, and C 1s core-level XPS data for the (<b>b</b>) 1 min and (<b>c</b>) 6 min UV-exposed hybrid films.</p> Full article ">Figure 5
<p>Optical transmittance graphs of the UV-curable polymer/AlSnO hybrid films according to UV-irradiation time for the wavelength range of 250–850 nm.</p> Full article ">Figure 6
<p>(<b>a</b>) POM images of the fabricated AP-LC cells assembled from 1 min, 3 min, and 6 min UV-exposed hybrid films (the directions of the analyzer (A) and polarizer (P) are presented by white arrows). (<b>b</b>) Schematic of the light path during passage through the AP-LC cell comprising uniformly aligned LCs on unidirectional hybrid films; no light leakage is observed.</p> Full article ">Figure 7
<p>(<b>a</b>) Oscillated transmittance graphs as functions of the incidence angle (from –70° to 70°) of the AP–LC cells produced from 1 min, 3 min, and 6 min UV–exposed hybrid films. (<b>b</b>) Irregular (with defects) and (<b>c</b>) uniform unidirectional surface hybrid–film-based AP–LC cells with their LC alignment state and corresponding front view.</p> Full article ">
17 pages, 3275 KiB  
Article
Luminescence and Structural Characterization of Gd2O2S Scintillators Doped with Tb3+, Ce3+, Pr3+ and F for Imaging Applications
by Alessia De Martinis, Luigi Montalto, Lorenzo Scalise, Daniele Rinaldi, Paolo Mengucci, Christos Michail, George Fountos, Nicki Martini, Vaia Koukou, Ioannis Valais, Athanasios Bakas, Christine Fountzoula, Ioannis Kandarakis and Stratos David
Crystals 2022, 12(6), 854; https://doi.org/10.3390/cryst12060854 - 17 Jun 2022
Cited by 5 | Viewed by 2824
Abstract
Radiodiagnostic technologies are powerful tools for preventing diseases and monitoring the condition of patients. Medicine and sectors such as industry and research all use this inspection methodology. This field demands innovative and more sophisticated systems and materials for improving resolution and sensitivity, leading [...] Read more.
Radiodiagnostic technologies are powerful tools for preventing diseases and monitoring the condition of patients. Medicine and sectors such as industry and research all use this inspection methodology. This field demands innovative and more sophisticated systems and materials for improving resolution and sensitivity, leading to a faster, reliable, and safe diagnosis. In this study, a large characterization of gadolinium oxysulfide (Gd2O2S) scintillator screens for imaging applications has been carried out. Seven scintillator samples were doped with praseodymium (Pr3+), terbium (Tb3+) activators and co-doped with praseodymium, cerium, and fluorine (Gd2O2S:Pr,Ce,F). The sample screens were prepared in the laboratory in the form of high packing density screens, following the methodology used in screen sample preparation in infrared spectroscopy and luminescence. Parameters such as quantum detection efficiency (QDE), energy absorption efficiency (EAE), and absolute luminescence efficiency (ALE) were evaluated. In parallel, a structural characterization was performed, via XRD and SEM analysis, for quality control purposes as well as for correlation with optical properties. Spatial resolution properties were experimentally evaluated via the Modulation Transfer Function. Results were compared with published data about Gd2O2S:Pr,Ce,F screens produced with a standard method of a sedimentation technique. In particular, the ALE rose with the X-ray tube voltage up to 100 kVp, while among the different dopants, Gd2O2S:Pr exhibited the highest ALE value. When comparing screens with different thicknesses, a linear trend for the ALE value was not observed; the highest ALE value was measured for the 0.57 mm thick Gd2O2S:Pr,Ce,F sample, while the best MTF values were found in the thinner Gd2O2S:Pr,Ce,F screen with 0.38 mm thickness. Full article
(This article belongs to the Section Inorganic Crystalline Materials)
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<p>X-ray energy fluence spectra <math display="inline"><semantics> <mrow> <mrow> <mo>(</mo> <mrow> <msub> <mi mathvariant="sans-serif">Ψ</mi> <mn>0</mn> </msub> </mrow> <mo>)</mo> </mrow> </mrow> </semantics></math> produced at 70, 100, and 130 kVp.</p> Full article ">Figure 2
<p>Experimental setup for the measurement of the emitted light energy flux comprising the integrating sphere, the PMT, and the vibrating reed electrometer.</p> Full article ">Figure 3
<p>XRD patterns of GOS screens doped with different activators. Miller indices are reported for peaks of the Gd<sub>2</sub>O<sub>2</sub>S compound. The unindexed peaks are due to KBr.</p> Full article ">Figure 4
<p>(<b>a</b>) SEM image of Gd<sub>2</sub>O<sub>2</sub>S screens showing the distribution of Gd<sub>2</sub>O<sub>2</sub>S (brighter regions) and KBr (darker regions) compounds. (<b>b</b>) EDS micro-analysis spectrum detecting main elements composing screens.</p> Full article ">Figure 5
<p>(<b>a</b>) Energy absorption efficiency (EAE) of Gd<sub>2</sub>O<sub>2</sub>S powder screens as a function of X-ray tube voltages. (<b>b</b>) Quantum detection efficiency (QDE) of Gd<sub>2</sub>O<sub>2</sub>S powder screens as a function of X-ray tube voltages. Points correspond to calculated values (from 50 kVp to 130 kVp). All screens with the same thickness d = 0.38 mm gave the same results, so the points in the figure are superimposed. (<b>c</b>) Energy absorption efficiency (EAE) as a function of the thickness. (<b>d</b>) Quantum detection efficiency (QDE) as a function of the thickness. The solid lines in the graphs are guides for the eyes.</p> Full article ">Figure 5 Cont.
<p>(<b>a</b>) Energy absorption efficiency (EAE) of Gd<sub>2</sub>O<sub>2</sub>S powder screens as a function of X-ray tube voltages. (<b>b</b>) Quantum detection efficiency (QDE) of Gd<sub>2</sub>O<sub>2</sub>S powder screens as a function of X-ray tube voltages. Points correspond to calculated values (from 50 kVp to 130 kVp). All screens with the same thickness d = 0.38 mm gave the same results, so the points in the figure are superimposed. (<b>c</b>) Energy absorption efficiency (EAE) as a function of the thickness. (<b>d</b>) Quantum detection efficiency (QDE) as a function of the thickness. The solid lines in the graphs are guides for the eyes.</p> Full article ">Figure 6
<p>In the emission spectrum we can recognize the Gd<sub>2</sub>O<sub>2</sub>S:Tb screen with its main peaks at 475 nm and 550 nm; the Gd<sub>2</sub>O<sub>2</sub>S:Pr screen with its main peaks at 512 nm and 668 nm; and the Gd<sub>2</sub>O<sub>2</sub>S:Pr,Ce,F screen with its max peak at 513 nm.</p> Full article ">Figure 7
<p>(<b>a</b>) Absolute luminescence efficiency (ALE) of Gd<sub>2</sub>O<sub>2</sub>S:Pr,Ce,F powder screens with different thicknesses and same dopant agents. (<b>b</b>) ALE of Gd<sub>2</sub>O<sub>2</sub>S powder screens with different dopants and same thickness. The vertical axis units are E.U. values (1 E.U equal to μW m<sup>−2</sup>/ mR s<sup>−1</sup>). The solid lines in the graphs are guides for the eyes.</p> Full article ">Figure 8
<p>The ALE as a function of thickness for GOS:Pr,Ce,F for different X-ray tube voltages. The solid lines in the graphs are guides for the eyes.</p> Full article ">Figure 9
<p>(<b>a</b>) Comparison of the MTFs of Gd<sub>2</sub>O<sub>2</sub>S:Pr,Ce,F employed in the Kodak Min-R screens as measured experimentally in transmission mode 1 cycle mm<sup>−1</sup> = 1 lp mm<sup>−1</sup>. (<b>b</b>) cycles/mm@10% of Gd<sub>2</sub>O<sub>2</sub>S:Pr,Ce,F as a function of the screens’ thickness. The solid line in the graphs is a guide for the eyes.</p> Full article ">
8 pages, 1735 KiB  
Article
Stoichiometric Growth of Monolayer FeSe Superconducting Films Using a Selenium Cracking Source
by Kejing Zhu, Heng Wang, Yuying Zhu, Yunyi Zang, Yang Feng, Bingbing Tong, Dapeng Zhao, Xiangnan Xie, Kai Chang, Ke He and Chong Liu
Crystals 2022, 12(6), 853; https://doi.org/10.3390/cryst12060853 - 17 Jun 2022
Cited by 1 | Viewed by 2093
Abstract
As a novel interfacial high-temperature superconductor, monolayer FeSe on SrTiO3 has been intensely studied in the past decade. The high selenium flux involved in the traditional growth method complicates the film’s composition and entails more sample processing to realize the superconductivity. Here [...] Read more.
As a novel interfacial high-temperature superconductor, monolayer FeSe on SrTiO3 has been intensely studied in the past decade. The high selenium flux involved in the traditional growth method complicates the film’s composition and entails more sample processing to realize the superconductivity. Here we use a Se cracking source for the molecular beam epitaxy growth of FeSe films to boost the reactivity of the Se flux. Reflection high-energy electron diffraction shows that the growth rate of FeSe increases with the increasing Se flux when the Fe flux is fixed, indicating that the Se over-flux induces Fe vacancies. Through careful tuning, we find that the proper Se/Fe flux ratio with Se cracked that is required for growing stoichiometric FeSe is close to 1, much lower than that with the uncracked Se flux. Furthermore, the FeSe film produced by the optimized conditions shows high-temperature superconductivity in the transport measurements without any post-growth treatment. Our work reinforces the importance of stoichiometry for superconductivity and establishes a simpler and more efficient approach to fabricating monolayer FeSe superconducting films. Full article
(This article belongs to the Special Issue Superconductors: Materials, Microstructures and Applications)
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<p>Selenium flux measured by a QCM as a function of the reservoir temperature while keeping the cracking zone at 1000 °C. Red and blue data points are from two sets of measurements a month apart. The yellow band is a guide for the eye. The Fe flux is fixed in this study, indicated by the green dashed line. The flux unit is converted to number of layers per minute, considering the density of the element in the tetragonal FeSe. The inset is a schematic of the Se cracker.</p> Full article ">Figure 2
<p>RHEED images of (<b>a</b>) treated STO substrate, (<b>b</b>) FeSe film grown for 5 min with Se(185/1000), and (<b>c</b>) FeSe film grown for 5 min with Se(200/600). The additional spots marked by the arrows in (<b>c</b>) indicate the formation of Fe islands.</p> Full article ">Figure 3
<p>RHEED characterization on the growth of FeSe for different Se fluxes. (<b>a</b>–<b>d</b>) RHEED images of monolayer FeSe grown with various Se flux as labeled on the figures. (<b>e</b>–<b>h</b>) Real-time RHEED intensity of (00), (01), and (02) diffractions during growth, corresponding to the samples in (<b>a</b>–<b>d</b>). The integrated areas are marked on (<b>a</b>) and are the same for (<b>b</b>–<b>d</b>). The red dashed lines in (<b>e</b>–<b>h</b>) indicate the time at which the first layer FeSe is completed.</p> Full article ">Figure 4
<p>Resistance-temperature curves of a 1.5-layer FeSe film grown with Se(180,1000) in the magnetic field of 0 T and 3 T (B//c). The film is capped with 10 layer FeTe.</p> Full article ">
10 pages, 2971 KiB  
Article
Crystallization Kinetics of the Fe68Nb6B23Mo3 Glassy Ribbons Studied by Differential Scanning Calorimetry
by Yongqin Liu, Man Zhu, Yuanyuan Du, Lijuan Yao and Zengyun Jian
Crystals 2022, 12(6), 852; https://doi.org/10.3390/cryst12060852 - 17 Jun 2022
Cited by 3 | Viewed by 1757
Abstract
Fe-based metallic glass has wide industrial application due to its unique mechanical behavior and magnetic properties. In the present work, the non-isothermal crystallization kinetics in Fe68Nb6B23Mo3 glassy alloys were investigated by differential scanning calorimeter (DSC). The [...] Read more.
Fe-based metallic glass has wide industrial application due to its unique mechanical behavior and magnetic properties. In the present work, the non-isothermal crystallization kinetics in Fe68Nb6B23Mo3 glassy alloys were investigated by differential scanning calorimeter (DSC). The results indicate that both the glass transformation and crystallization process display an obvious kinetic effect. The activation energy is calculated using Kissinger’s method and Ozawar’s method. The activation energy for Tg (glass transition temperatures), Tx (crystallization initiation temperatures) and Tp (crystallization peak temperatures) calculated from Kissinger equation, is 308 ± 4, 342 ± 5 and 310 ± 7 kJ mol−1, respectively. The activation energy for Tg, Tx and Tp calculated from Ozawa equation is 322 ± 3, 356 ± 5 and 325 ± 7 kJ mol−1, respectively. With the increase of the crystallization volume fraction x, the Avrami exponent n(x) first decreases and then increases. At the preliminary step, 0 < x < 0.25, 2.5 < n(x) < 4.0 stands for the growth from a small size with an increasing nucleation rate. When 0.25 < x < 0.71, n(x) decreases from 2.5 to 1.5, indicating that this stage is controlled by the growth of small particles with a decreasing nucleation rate. Full article
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<p>XRD pattern of the melt-spun Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> ribbons.</p> Full article ">Figure 2
<p>DSC traces for the Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> glassy alloys under varied heating rates.</p> Full article ">Figure 3
<p>Kissinger plots of the Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> glassy alloys.</p> Full article ">Figure 4
<p>Ozawa plots of the Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> glassy alloys.</p> Full article ">Figure 5
<p>The <span class="html-italic">x</span>-<span class="html-italic">T</span> curves of the Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> glassy alloys under various heating rates.</p> Full article ">Figure 6
<p>Plots of ln<span class="html-italic">β</span> verse 1000/<span class="html-italic">T</span>(<span class="html-italic">x</span>) of the Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> glassy alloys.</p> Full article ">Figure 7
<p>Relationship between local activation energy <span class="html-italic">E</span>(<span class="html-italic">x</span>) and the crystallization volume fraction <span class="html-italic">x</span>.</p> Full article ">Figure 8
<p>Plots of ln(−ln(1 − <span class="html-italic">x</span>)) against 1000/<span class="html-italic">T</span> of the Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> metallic glass (at 10\20\30\40 K/min).</p> Full article ">Figure 9
<p>The variation of local Avrami exponent <span class="html-italic">n</span>(<span class="html-italic">x</span>) as a function of the crystallization volume fraction at heating rate of 20 K/min.</p> Full article ">Figure 10
<p>Relationship between ln<span class="html-italic">β</span> and characteristic temperatures of the Fe<sub>68</sub>Nb<sub>6</sub>B<sub>23</sub>Mo<sub>3</sub> glassy alloys.</p> Full article ">
14 pages, 4762 KiB  
Article
Effects of Basicity and Al2O3 Content on Viscosity and Crystallization Behavior of Super-High-Alumina Slag
by Shuai Wang, Ying Jiang, Yufeng Guo, Zhuang Yang, Feng Chen, Lingzhi Yang and Guang Li
Crystals 2022, 12(6), 851; https://doi.org/10.3390/cryst12060851 - 16 Jun 2022
Cited by 7 | Viewed by 2238
Abstract
The CaO-SiO2-MgO-Al2O3 slags with high alumina content are widely applied in various pyrometallurgical processes. However, for super-high-alumina slags, especially for those with alumina content of more than 25 wt%, there is a lack of relevant studies about the [...] Read more.
The CaO-SiO2-MgO-Al2O3 slags with high alumina content are widely applied in various pyrometallurgical processes. However, for super-high-alumina slags, especially for those with alumina content of more than 25 wt%, there is a lack of relevant studies about the properties of slag. The melting behavior, viscosity, structural property, and crystallization behavior of high-alumina slag with the fixed MgO content of 11.13 wt% and Al2O3 content from 27.61 wt% to 40 wt% were investigated. The results revealed that the liquidus temperatures and complete solidification temperatures of slag increased with the increasing binary basicity and Al2O3 content. The melting temperature and viscosity of the CaO-SiO2-11.13wt%MgO-Al2O3 slag system increased with the increasing basicity from 0.8 to 1 and Al2O3 content from 27.61 wt% to 40 wt%. The increase in Al2O3 caused the formation of high-crystallinity and high melting point materials in the slag, such as spinel and Åkermanite. A large number of non-uniform phases could quickly crystallize out of the solids present in the slag melt, thereby increasing the slag viscosity and deteriorating the fluidity of the slag. Full article
(This article belongs to the Topic Iron Concentrate Particles)
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<p>XRD pattern of blast furnace slag.</p> Full article ">Figure 2
<p>Schematic diagram of the slag viscosity measurement device.</p> Full article ">Figure 3
<p>Melting characteristic temperature (DT—deformation temperature; ST—spherical temperature; HT—hemispherical temperature; FT—flowing temperature).</p> Full article ">Figure 4
<p>Phase diagram of CaO-SiO<sub>2</sub>-Al<sub>2</sub>O<sub>3</sub>-11.13wt%MgO calculated by 8.0.</p> Full article ">Figure 5
<p>Equilibrium phase compositions of the high-alumina slags at various temperatures. (<b>a</b>) B = 0.8, (<b>b</b>) B = 0.9, (<b>c</b>) B = 1.0, (<b>d</b>)B = 1.1, (<b>e</b>) B = 0.9, Al<sub>2</sub>O<sub>3</sub> = 35 wt%, (<b>f</b>) B = 0.9, Al<sub>2</sub>O<sub>3</sub> = 40 wt%, (<b>g</b>) B = 1.1, Al<sub>2</sub>O<sub>3</sub> = 40 wt%, and (<b>h</b>) the liquidus temperatures and complete solidification temperatures.</p> Full article ">Figure 6
<p>Effects of the slag basicity on the melting temperature of high-alumina slag (Al<sub>2</sub>O<sub>3</sub> = 27.61 wt%; MgO = 11.13 wt%).</p> Full article ">Figure 7
<p>Effects of the Al<sub>2</sub>O<sub>3</sub> content on the melting temperature of high-alumina slag. (B = 0.9, Al<sub>2</sub>O<sub>3</sub> = 27.61 wt%).</p> Full article ">Figure 8
<p>Effects of temperature on the viscosity of slag with different basicity (Al<sub>2</sub>O<sub>3</sub> = 27.61 wt%; MgO = 11.13 wt%).</p> Full article ">Figure 9
<p>Effects of temperature on the viscosity of slag with different Al<sub>2</sub>O<sub>3</sub> content (B = 0.9; MgO = 11.13 wt%).</p> Full article ">Figure 10
<p>Effects of basicity (<b>a</b>) and Al<sub>2</sub>O<sub>3</sub> content (<b>b</b>) on the viscosity of the CaO-SiO<sub>2</sub>-MgO-Al<sub>2</sub>O<sub>3</sub> slags.</p> Full article ">Figure 11
<p>Comparisons of the effects of basicity (<b>a</b>) and Al<sub>2</sub>O<sub>3</sub> content (<b>b</b>) on the viscosity of the CaO-SiO<sub>2</sub>-MgO-Al<sub>2</sub>O<sub>3</sub> slags at 1500 °C [<a href="#B9-crystals-12-00851" class="html-bibr">9</a>,<a href="#B12-crystals-12-00851" class="html-bibr">12</a>,<a href="#B38-crystals-12-00851" class="html-bibr">38</a>].</p> Full article ">Figure 12
<p>FT–IR transmittance spectra of CaO–SiO<sub>2</sub>–MgO–Al<sub>2</sub>O<sub>3</sub> slag with different basicity values.</p> Full article ">Figure 13
<p>Variation of the main phases (liquid phase and solid phase) for high-alumina slag with different basicity and Al<sub>2</sub>O<sub>3</sub> content at 1500 °C (FeO = 1.63%; MnO = 1.36%; TiO<sub>2</sub> = 0.58%; P (O<sub>2</sub>) = 1.0 × 10<sup>−16</sup> atm).</p> Full article ">Figure 14
<p>XRD patterns of the slowly cooled slag with different basicity (S-Spinel (MgAl<sub>2</sub>O<sub>4</sub>); A-Åkermanite (Ca<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>)).</p> Full article ">Figure 15
<p>XRD patterns of the slowly cooled slag with different Al<sub>2</sub>O<sub>3</sub> content and basicity (S-Spinel (MgAl<sub>2</sub>O<sub>4</sub>); A-Åkermanite (Ca<sub>2</sub>MgSi<sub>2</sub>O<sub>7</sub>)).</p> Full article ">Figure 16
<p>The effects of basicity and Al<sub>2</sub>O<sub>3</sub> content on the microstructure of high-alumina slag. (<b>a</b>) B = 0.8, (<b>b</b>) B = 0.9, (<b>c</b>) B = 1.0, (<b>d</b>) B = 1.1, (<b>e</b>) B = 0.9, Al<sub>2</sub>O<sub>3</sub> = 35 wt%, (<b>f</b>) B = 0.9, Al<sub>2</sub>O<sub>3</sub> = 40 wt%, (<b>g</b>) B = 1.1, Al<sub>2</sub>O<sub>3</sub> = 40 wt%, and (<b>h</b>) proportion of solid phase in high-alumina slag (determined by Image J software).</p> Full article ">
24 pages, 11106 KiB  
Article
Mechanical Response and Fracture of Pultruded Carbon Fiber/Epoxy in Various Modes of Loading
by Arie Bussiba, Ilan Gilad, Snir Lugassi, Sigal David, Jacob Bortman and Zohar Yosibash
Crystals 2022, 12(6), 850; https://doi.org/10.3390/cryst12060850 - 16 Jun 2022
Cited by 5 | Viewed by 2138
Abstract
Pultrusion is a continuous process of forming constant cross-sections of unidirectional composites with a significant long length. This unique process is implemented widely in the composites industry due to its continuous, automated, and highly productive nature. The current research focused on mechanical response [...] Read more.
Pultrusion is a continuous process of forming constant cross-sections of unidirectional composites with a significant long length. This unique process is implemented widely in the composites industry due to its continuous, automated, and highly productive nature. The current research focused on mechanical response characterization at three modes of loading: tensile, compression, and shear loading of coupons made from a graphite/epoxy 1 mm sheet. In addition, the effects of holes and notches were examined in terms of mechanical properties. The mechanical behavior was assessed through stress–strain curves with careful attention on the curve profile, macroscopic fracture modes observations, and optical microscopic tracking with continuous video records. The mechanical tests follow standards with some critiques on the shear test. Finite element analysis (FEA) was used to accurately determine the shear modulus, and for other mechanical investigations. By nature, under tension, the unidirectional fiber composite at 0° orientation exhibits high strength (2800 MPa), with very low strength at 90° orientation (40 MPa). Both orientations display linear mechanical behavior. Under compression, 0° orientation exhibits low strength (1175 MPa), as compared to tension due to the kinking phenomena, which is the origin in the deviation from linear behavior. Under shear, both orientations exhibit approximately the same shear strength (45 MPa for 0° and 47 MPa for 90°), which is mainly related to the mechanical properties of the epoxy resin. In general, in the presence of holes, the remote fracture stress in the various modes of loading did not change significantly, as compared to uniform coupons; however, some localized delamination crack growth occurred at the vicinity of the holes, manifested by load drops up to the final fracture. This behavior is also attributed to the tension of notched coupons. FEA shows that the shear values were unaffected by manufacturing imperfections, coupon thickness, and by asymmetrical gripping up to 3 mm, with minor effect in the case of a small deviation from the load line. Selected experimental tests support the FEA tendencies. Full article
(This article belongs to the Special Issue Advanced Aerospace Materials: Processing, Microstructure, Mechanical Properties and Applications)
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<p>Coupon dimensions and SG location, for each mode of loading; (<b>a</b>) tension; (<b>b</b>) compression; (<b>c</b>) shear.</p> Full article ">Figure 2
<p>Experimental set-up for the various modes of loading and SG location; (<b>a</b>) tension; (<b>b</b>) compression; (<b>c</b>) shear.</p> Full article ">Figure 3
<p>Stress–strain curves in tensile mode for different fibers orientations; (<b>a</b>) 0°; (<b>b</b>) 90°.</p> Full article ">Figure 4
<p>Tensile fracture modes for the 0° and the 90° coupons; (<b>a</b>) general view; (<b>b</b>) 0°; (<b>c</b>) 9°.</p> Full article ">Figure 5
<p>Stress–strain curves in compression mode for different orientations; (<b>a</b>) 0°; (<b>b</b>) 90°.</p> Full article ">Figure 6
<p>Compression fracture modes at different orientations; (<b>a</b>,<b>b</b>) top and side views, 90°; (<b>c</b>,<b>d</b>) top and side view, 0°; (<b>e</b>) the kinking phenomena.</p> Full article ">Figure 7
<p>Microscopic fracture modes obtained in compression; (<b>a</b>) general view; (<b>b</b>) serrated type fracture in the matrix epoxy resin.</p> Full article ">Figure 8
<p>Shear stress–strain curves for different orientations; (<b>a</b>) 0° entire curves up to fracture (3 coupons); (<b>b</b>) 90° entire curves up to fracture (two coupons); (<b>c</b>) 0° expanded zone where load relaxations were noticed; (<b>d</b>) comparison curves of 0° and 90° coupons (chose representative).</p> Full article ">Figure 9
<p>Sites of delamination cracks in DVN coupons for various orientations; (<b>a</b>) 0°; (<b>b</b>) 90°.</p> Full article ">Figure 10
<p>Microscopic fracture modes developed during shear at different orientations; (<b>a</b>,<b>b</b>) 0°; (<b>c</b>,<b>d</b>) 90°.</p> Full article ">Figure 11
<p>Mechanical response of holed coupons in terms of nominal stress; (<b>a</b>) stress–strain of 2.5 mm holed coupon; (<b>b</b>) stress –displacement full curves up to fracture; (<b>c</b>) expanded region where σ<sub>r</sub> is observed for the various holes’ diameter (the arrow indicates increasing in D).</p> Full article ">Figure 12
<p>The dependency of σ<sub>r</sub> with increasing hole diameter.</p> Full article ">Figure 13
<p>The change in the number and amount of stress relaxation with hole diameter.</p> Full article ">Figure 14
<p>The tensile fracture modes in the holed 0° coupons with different diameters; (<b>a</b>) general view; (<b>b</b>) 5.5 mm; (<b>c</b>) 8 mm (the dashed circles indicate the zone where the fracture occurred).</p> Full article ">Figure 15
<p>Microscopic fracture mode developed during tensile of holed coupons; (<b>a</b>) general view; (<b>b</b>) the chevron-type cracking of the epoxy resin between the carbon fibers.</p> Full article ">Figure 16
<p>Nominal stress vs. strain and displacement for various notched coupons; (<b>a</b>) stress vs. strain for ND = 1 mm; (<b>b</b>) stress vs. displacement curves up to fracture; (<b>c</b>) extended zone where load relaxations were detected.</p> Full article ">Figure 17
<p>Tensile fracture modes in the 0° orientation of notched coupons with ND-2.4 mm; (<b>a</b>) general view; (<b>b</b>) two ligaments left after fracture; (<b>c</b>) the fracture profile at the notch radius.</p> Full article ">Figure 18
<p>Stress vs. displacement in the compression mode, in the presence of various holes; (<b>a</b>) complete curves; (<b>b</b>) expanded regions where local load relaxation is observed.</p> Full article ">Figure 19
<p>Compression fracture mode in the 0° orientation of holed coupons with various hole diameter; (<b>a</b>) 2.5 mm; (<b>b</b>) 3.5 mm; (<b>c</b>) 4.5 mm; (<b>d</b>) 5.5 mm.</p> Full article ">Figure 20
<p>Macroscopic fracture modes in shear loading of holed coupons; (<b>a</b>) delamination cracks at the V-notch; (<b>b</b>) cracks occurring as a result of further loading at 5.5 mm holed coupon.</p> Full article ">Figure 21
<p>The hole and the notch effect on the mechanical response in tension; (<b>a</b>) first stress relaxation vs. hole diameter and notch depth; (<b>b</b>) fracture stress; (<b>c</b>) the amount and the number of stress relaxations.</p> Full article ">Figure 22
<p>Experimental curves used for the FEA procedure; (<b>a</b>) F vs. γ; (<b>b</b>) F vs. displacement; (<b>c</b>) FE model and boundary conditions.</p> Full article ">Figure 23
<p>(<b>a</b>,<b>b</b>) Normalized shear stress, as obtained by the FEA at p = 8, for 0° and 90° orientations, respectively; (<b>c</b>) computed compared to experimental force vs. shear strain.</p> Full article ">Figure 24
<p>(<b>a</b>,<b>b</b>) Possible sources that may be affecting the shear stress value; (<b>a</b>) defect in the notch radius (marked by arrows); (<b>b</b>) asymmetrical gripping, a ≠ b; (<b>c</b>) deviation from the load line marked by the angle α.</p> Full article ">Figure 25
<p>Radius profile and the angle notch for the shear coupon machined in (<b>a</b>) mechanical (arrow mark the defect) and (<b>b</b>) water cutting.</p> Full article ">Figure 26
<p>Stress concentration, as computed by a FEA at p = 8 at a notch (<b>a</b>,<b>c</b>) and at a hole (<b>b</b>,<b>d</b>) for the different predicted stresses: (<b>a</b>,<b>b</b>) σ<sub>yy</sub>, (<b>c</b>,<b>d</b>) τ<sub>xy</sub>.</p> Full article ">Figure 26 Cont.
<p>Stress concentration, as computed by a FEA at p = 8 at a notch (<b>a</b>,<b>c</b>) and at a hole (<b>b</b>,<b>d</b>) for the different predicted stresses: (<b>a</b>,<b>b</b>) σ<sub>yy</sub>, (<b>c</b>,<b>d</b>) τ<sub>xy</sub>.</p> Full article ">
10 pages, 3716 KiB  
Article
TiN–Fe Vertically Aligned Nanocomposites Integrated on Silicon as a Multifunctional Platform toward Device Applications
by Matias Kalaswad, Di Zhang, Bethany X. Rutherford, Juanjuan Lu, James P. Barnard, Zihao He, Juncheng Liu, Haohan Wang, Xiaoshan Xu and Haiyan Wang
Crystals 2022, 12(6), 849; https://doi.org/10.3390/cryst12060849 - 16 Jun 2022
Cited by 4 | Viewed by 2127
Abstract
Transition metal nitrides such as titanium nitride (TiN) possess exceptional mechanical-, chemical-, and thermal-stability and have been utilized in a wide variety of applications ranging from super-hard, corrosion-resistive, and decorative coatings to nanoscale diffusion barriers in semiconductor devices. Despite the ongoing interest in [...] Read more.
Transition metal nitrides such as titanium nitride (TiN) possess exceptional mechanical-, chemical-, and thermal-stability and have been utilized in a wide variety of applications ranging from super-hard, corrosion-resistive, and decorative coatings to nanoscale diffusion barriers in semiconductor devices. Despite the ongoing interest in these robust materials, there have been limited reports focused on engineering high-aspect ratio TiN-based nanocomposites with anisotropic magnetic and optical properties. To this end, we explored TiN–Fe thin films with self-assembled vertical structures integrated on Si substrates. We showed that the key physical properties of the individual components (e.g., ferromagnetism from Fe) are preserved, that vertical nanostructures promote anisotropic behavior, and interactions between TiN and Fe enable a special magneto-optical response. This TiN–Fe nanocomposite system presents a new group of complex multifunctional hybrid materials that can be integrated on Si for future Si-based memory, optical, and biocompatible devices. Full article
(This article belongs to the Special Issue Strain-Engineered Nanocomposites towards Multifunctionalities)
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<p>The schematic of the pseudo-composite TiN–Fe target with a Fe strip attached to a TiN disk. Pulsed laser deposition was used to deposit TiN–Fe vertically aligned nanocomposite thin films on Si substrates.</p> Full article ">Figure 2
<p>(<b>a</b>) X-ray diffraction <span class="html-italic">θ–2θ</span> patterns of the TiN–Fe thin films deposited on Si (001) substrates with and without a TiN buffer layer and (<b>b</b>) the local measurement centered around 43° to distinguish the TiN (002) and Fe (110) peaks.</p> Full article ">Figure 3
<p>The cross-sectional nanostructure of the TiN–Fe vertically aligned nanocomposites revealed by STEM with EDS. The STEM image of (<b>a</b>) TiN–Fe deposited on bare Si and corresponding (<b>b</b>) Ti, (<b>c</b>) Fe, and (<b>d</b>) composite Ti, Fe, and Si elemental maps. The STEM image of (<b>e</b>) TiN–Fe deposited on TiN-buffered Si and corresponding (<b>f</b>) Ti, (<b>g</b>) Fe, and (<b>h</b>) composite Ti, Fe, and Si elemental maps.</p> Full article ">Figure 4
<p>Room temperature in-plane and out-of-plane magnetic hysteresis loops of the TiN–Fe films grown without a TiN buffer (<b>left</b>) and with a TiN buffer (<b>right</b>).</p> Full article ">Figure 5
<p>Real (<b>left</b>) and imaginary (<b>right</b>) parts of the in-plane and out-of-plane permittivities of the TiN–Fe nanocomposite films deposited on the bare Si and with a TiN buffer.</p> Full article ">Figure 6
<p>The room temperature polar and longitudinal magneto-optical Kerr effect data of the TiN–Fe films grown without a TiN buffer (<b>left</b>) and with a TiN buffer (<b>right</b>).</p> Full article ">
12 pages, 3318 KiB  
Article
Evolution of Structure and Properties of Micro-Nano Structure 2507 Duplex Stainless Steel Prepared by Aluminothermic Reduction
by Faqi Zhan, Xiao Liu, Hua Zhang, Keliang Wang, Shipeng Xu, Min Zhu, Yuehong Zheng and Peiqing La
Crystals 2022, 12(6), 848; https://doi.org/10.3390/cryst12060848 - 16 Jun 2022
Cited by 3 | Viewed by 1810
Abstract
In this work, a large ingot of micro-nano structure 2507 duplex stainless steel was prepared in a single step using the aluminothermic reaction method. Chromium having different excess fractions were added to reaction powders to make up for evaporation loss, and the results [...] Read more.
In this work, a large ingot of micro-nano structure 2507 duplex stainless steel was prepared in a single step using the aluminothermic reaction method. Chromium having different excess fractions were added to reaction powders to make up for evaporation loss, and the results show that the composition and structure of 2507 duplex stainless steel with a chromium excess ratio of 70% are satisfactory. The volume fraction of nanocrystalline in as-cast alloy was 41% and the average grain size was 34 nm. Additionally, the anticipated steels were rolled roughly with deformation of 40% at 1000 °C and followed by fine rolling with deformation of 30, 50 and 70%, separately, at 800 °C. Then, the effects of rolling deformation and precipitation on mechanical properties were studied in detail. Compared with the as-cast alloy, there was no phase transformation in the alloys with deformation of 30 and 50%, and they were still composed of γ and α phases, whereas the σ phase appeared in the alloy with deformation of 70%. When the deformation was 50%, the rolled alloy achieved the best performance, and the tensile strength, yield strength, and elongation were 912 MPa, 523 MPa, and 24.3%, respectively. Full article
(This article belongs to the Special Issue Structural Changes during Steel Processing)
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<p>Schematic diagram of tensile sample (unit in mm).</p> Full article ">Figure 2
<p>The X-ray diffractometer patterns of 2507 duplex stainless steels prepared with excessive Cr of 50, 70 and 100%.</p> Full article ">Figure 3
<p>SEM image of 2507 duplex stainless steel prepared with excessive Cr of 70%.</p> Full article ">Figure 4
<p>The transmission electron microscope images of as-cast 2507 duplex stainless steels: (<b>a</b>) bright field image; (<b>b</b>) dark field image; (<b>c</b>) selected area electron diffraction pattern; (<b>d</b>) histogram of nanocrystalline grain size distribution.</p> Full article ">Figure 5
<p>The XRD patterns of hot-rolled 2507 duplex stainless steels.</p> Full article ">Figure 6
<p>The EPMA backscattered electron images (BEIs) of hot-rolled 2507 duplex stainless steels and their corresponding element mappings: (<b>a</b>) HR-30%; (<b>b</b>) HR-50%; and (<b>c</b>) HR-70%.</p> Full article ">Figure 7
<p>Mechanical properties of hot-rolled 2507 duplex stainless steel: (<b>a</b>) stress–strain curves; (<b>b</b>) strength and elongation; (<b>c</b>) hardness.</p> Full article ">Figure 8
<p>Fracture morphologies of hot-rolled 2507 duplex stainless steels: (<b>a</b>) HR-30%; (<b>b</b>) HR-50%; and (<b>c</b>) HR-70%.</p> Full article ">
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