Abstract. Complex microstructure analysis of TiN/Ti/a-C:H multilayer coatings, subjected to mecha... more Abstract. Complex microstructure analysis of TiN/Ti/a-C:H multilayer coatings, subjected to mechanical and biological tests, were performed by means of transmission electron microscopy (TEM) and confocal scanning laser microscopy (CSLM), respectively. Influence of interface numbers and phase ratios on coating properties was studied. Thin films were fabricated by a hybrid PLD technique (PLD supported by magnetron sputtering). The a-C:H phase was characterized by an amorphous structure, while TiN was built of columnar crystallites. Multilayer coatings contained sequentially deposited TiN and a-C:H layers with thin metallic Ti inter- layers deposited at each interface. Mechanisms of mechanical wear of analyzed systems were presented focusing on the cracking propagation revealed in the scratch test. Biological tests were done basing on smooth muscle cells adhesion to coating surfaces. An increase of TiN phase in the coating led to improvement of mechanical properties, while the carbon p...
Bio-tribological multilayer PVD coatings deposited on stainless steel substrates have been studie... more Bio-tribological multilayer PVD coatings deposited on stainless steel substrates have been studied on multiple scales. Anodic dissolution as a precursor of the pitting corrosion mechanisms operating in layers was described. Advanced Zr/ZrxN and Zr/ZrxN+a-C:H nano-multilayer coatings with different layer thickness ratios (metallic to ceramic) were subjected to corrosion-resistant properties analysis. Materials protected by the Zr/Zr2N(1:4 ratio) + a-C:H coating exhibited the lowest corrosion resistance in the test solution because of the corrosion behaviour of this coating was controlled by the defects content, while corrosion of coatings without additional a-C:H layer was controlled by oxidation of the nitride to form an oxide over-layer. Microstructure characterization was performed on the micro, nano and atomic scales using transmission electron microscopy techniques. It allowed to described the differences of corrosion protection of applied different coatings. The possibility of ...
The paper presents the results of mechanical and tribological tests of two kinds of carbon coatin... more The paper presents the results of mechanical and tribological tests of two kinds of carbon coatings with advanced microstructures - nanocomposite CrC/a-C:H and multilayer TiN/Ti/a-C:H. The introduction of barriers for dislocation motion and microcrack propagation as CrC nanograins in nanocomposite coating or Ti and TiN interlayers in multilayer led to coatings hardening and improved fracture and wear resistance in comparison to a single amorphous a-C:H coating. It was confirmed by wide range of mechanical tests. The mechanism of microcrack deflection and splitting on CrC nanograins and Ti layers was studied using spherical indentation tests and TEM observations of indent cross-sections.
Microstructure characterization of an as deposited coating; (a) image obtained using SEM; (b) ima... more Microstructure characterization of an as deposited coating; (a) image obtained using SEM; (b) image done by TEM technique in STEM mode. Microstructure characterization of the coating at the cross-section, done by TEM; (a) TEM BF image; (b) STEM image.
ABSTRACT Development of a new generation of multilayer coatings as well as a microstructure under... more ABSTRACT Development of a new generation of multilayer coatings as well as a microstructure understanding of the mechanisms operating at the smallest length scale (nano- and atomic-scale) during wear, opens an avenue for the fabrication of future high-tech functional surfaces. Coatings for the presented work were fabricated by a pulsed laser deposition supported by magnetron sputtering. Microstructure characterization has been performed on as-deposited coatings as well as on coatings after mechanical wear test. Thin foils for detailed TEM microstructure observation were cut directly from the mechanically deformed area, using the FIB technique. Wear mechanisms operating at the small length scale of TiN/Ti/a-C:H multilayer coatings subjected to mechanical wear was studied by means of transmission electron microscopy (TEM). Cracking of the multilayer systems propagated layer by layer. The highest stress concentration during mechanical uploading was moved through the multilayer coating by breaking only one layer at the time.
Studies of advanced protective chromium‐based coatings on the carbon fibre composite (CFC) were p... more Studies of advanced protective chromium‐based coatings on the carbon fibre composite (CFC) were performed. Multidisciplinary examinations were carried out comprising: microstructure transmission electron microscopy (TEM, HREM) studies, micromechanical analysis and wear resistance. Coatings were prepared using a magnetron sputtering technique with application of high‐purity chromium and carbon (graphite) targets deposited on the CFC substrate. Selection of the CFC for surface modification in respect to irregularities on the surface making the CFC surface more smooth was performed. Deposited coatings consisted of two parts. The inner part was responsible for the residual stress compensation and cracking initiation as well as resistance at elevated temperatures occurring namely during surgical tools sterilization process. The outer part was responsible for wear resistance properties and biocompatibility. Experimental studies revealed that irregularities on the substrate surface had a negative influence on the crystallites growth direction. Chromium implanted into the a‐C:H structure reacted with carbon forming the cubic nanocrystal chromium carbides of the Cr23C6 type. The cracking was initiated at the coating/substrate interface and the energy of brittle cracking was reduced because of the plastic deformation at each Cr interlayer interface. The wear mechanism and cracking process was described in micro‐ and nanoscale by means of transmission electron microscope studies. Examined materials of coated CFC type would find applications in advanced surgical tools.
Carbon fiber structures provide strength, stiffness, and fatigue resistance. Carbon-based materia... more Carbon fiber structures provide strength, stiffness, and fatigue resistance. Carbon-based materials show, however, significant oxidative degradation in air beginning at temperatures in the region of 400 °C. Therefore, a coating concept for carbon–carbon composites consists of an inner part, which serves as a structural link with stress compensation ability to the carbon substrate, and an outer part, which acts as a diffusion barrier. In the presented paper, chromium/chromium nitride (Cr/CrN) multilayer structure has been selected as the inner part. The outer part of the coating, in the presented paper, was hydrogenated amorphous carbon (a-C:H). Among doping metals, Cr, as one of the carbide formed elements, possesses an attractive combination of properties (corrosion resistance, wear resistance, etc.). Thus, in the presented paper, a-C:H part of the coating was implanted by Cr nanocrystals. Coatings were deposited by means of magnetron sputtering technique. They were subjected to co...
Abstract Requirements for tribological protective coatings for medical tools, which would increas... more Abstract Requirements for tribological protective coatings for medical tools, which would increase their wear and corrosion resistance, are very high. The presented paper deals with novel nano-composite, multilayer protective coatings for tissue interaction elaboration and their diagnosis on metallic substrates. A hybrid pulsed laser deposition system was used for coating deposition. In the presented work, nano-composite Cr/CrN + [Cr/a-C : H implanted by metallic nanocrystals] multilayer coatings were developed for surface protection. The mechanical properties of the coatings were investigated by means of micro-hardness and elasticity modulus measurements. Bio-medical tests were conducted using eukaryotic cells. Microstructural analysis by means of transmission electron microscopy indicated that chromium which was implanted into a-C : H layers reacted with carbon forming chromium carbides.
Bioinspired, Biomimetic and Nanobiomaterials, 2014
The current work explains the influence of the polymer substrate on the topography formation of n... more The current work explains the influence of the polymer substrate on the topography formation of nano-wrinkled thin titanium films. Similar to the biomimetic antetype of human skin, this wrinkling phenomenon increases the elastic deformability of hard materials under tensile loading by flattening the wrinkled waves before high tensile stresses occur. Low energetic plasma deposition in direct current magnetron sputtering leads to smoother films with equiaxed domed wrinkle topography without a distinct preferred orientation on polymers (polyethylene terephthalate, polycarbonate, thermoplastic polyurethane). These domes are at least one order of magnitude larger than the commonly found topography on stiff silicon and correlates to the size of crystalline spherulites and segments in the applied semi- and pseudo-crystalline polymers. High energetic plasma deposition in pulsed laser deposition results in denser films with stretching of wrinkles. Higher intrinsic stresses require for relaxa...
Chromium carbonitride (CrCxN1−x) coatings are becoming more and more interesting for wear protect... more Chromium carbonitride (CrCxN1−x) coatings are becoming more and more interesting for wear protection applications due to their increased hardness and improved wear performance compared to chromium nitride (CrNx) hard coatings. Further improvements seem to be possible by using multilayer coatings of these two materials. In the current work such multilayer structures were deposited by the Pulsed Laser Deposition (PLD) technique
Multilayer Cr/CrN/Cr/Cr(N,C) and Cr/CrN with 8 and 32 layer coatings were deposited on austenite ... more Multilayer Cr/CrN/Cr/Cr(N,C) and Cr/CrN with 8 and 32 layer coatings were deposited on austenite substrates using pulsed laser deposition (PLD) technique. The microstructure observations were performed using Philips CM20trade mark, TECNAI G(2) F20 - TWINtrade mark and JEOL EX4000trade mark transmission microscopes. The performed experiments indicated that lowering the argon flow from 60 to 30 cm(3)/s during chromium ablation changes buffer layers microstructure from nearly amorphous to nano-crystalline. The nitride or carbo-nitride layers turned out to be less sensitive to changes in nitrogen flow during deposition. The columnar microstructure of Cr layers is coarser than those in CrN ones under the same deposition condition. This observation proved also that relying on PLD technique as thin as 30 nm layers might be formed within multilayer Cr/CrN coatings.
Archives of Civil and Mechanical Engineering, 2013
ABSTRACT This work is focused on the bio-inspired design of hard and tough multilayer coatings of... more ABSTRACT This work is focused on the bio-inspired design of hard and tough multilayer coatings of titanium (Ti) and titanium nitride (TiN) to reach both favourable mechanical and tribological behaviour. Biomimetic ideal is nacre, which is the inner layer of mollusk shell and both hard and tough. This combination of contrary material properties is due to its multilayered structure of thin aragonite tablets with dovetail geometry and nano-scaled protein binding interlayers. Transmission electron studies of the magnetron sputtered coatings on soft austenite substrate revealed either brittle behaviour of single layer TiN coatings (through-thickness cohesive coating fracture) or tough properties of multilayered structures (TiN layer fracture and Ti layer plastic deformation in deformation lines). The deformation mechanisms of Ti in between the TiN layers in the crack bands are result of strain hardening and separation of the crack edges in TiN: This broadens the deformation zone and prevents early fracture. The formed wave-like structure shows similar function as the dovetail-structure of aragonite tablets in nacre. Tribology in nacre is based on shearing of tablets. Wear in multilayered Ti–TiN structures is a result of cohesive film fracture and subsequent fatigue of the coating–substrate interface.
Abstract. Complex microstructure analysis of TiN/Ti/a-C:H multilayer coatings, subjected to mecha... more Abstract. Complex microstructure analysis of TiN/Ti/a-C:H multilayer coatings, subjected to mechanical and biological tests, were performed by means of transmission electron microscopy (TEM) and confocal scanning laser microscopy (CSLM), respectively. Influence of interface numbers and phase ratios on coating properties was studied. Thin films were fabricated by a hybrid PLD technique (PLD supported by magnetron sputtering). The a-C:H phase was characterized by an amorphous structure, while TiN was built of columnar crystallites. Multilayer coatings contained sequentially deposited TiN and a-C:H layers with thin metallic Ti inter- layers deposited at each interface. Mechanisms of mechanical wear of analyzed systems were presented focusing on the cracking propagation revealed in the scratch test. Biological tests were done basing on smooth muscle cells adhesion to coating surfaces. An increase of TiN phase in the coating led to improvement of mechanical properties, while the carbon p...
Bio-tribological multilayer PVD coatings deposited on stainless steel substrates have been studie... more Bio-tribological multilayer PVD coatings deposited on stainless steel substrates have been studied on multiple scales. Anodic dissolution as a precursor of the pitting corrosion mechanisms operating in layers was described. Advanced Zr/ZrxN and Zr/ZrxN+a-C:H nano-multilayer coatings with different layer thickness ratios (metallic to ceramic) were subjected to corrosion-resistant properties analysis. Materials protected by the Zr/Zr2N(1:4 ratio) + a-C:H coating exhibited the lowest corrosion resistance in the test solution because of the corrosion behaviour of this coating was controlled by the defects content, while corrosion of coatings without additional a-C:H layer was controlled by oxidation of the nitride to form an oxide over-layer. Microstructure characterization was performed on the micro, nano and atomic scales using transmission electron microscopy techniques. It allowed to described the differences of corrosion protection of applied different coatings. The possibility of ...
The paper presents the results of mechanical and tribological tests of two kinds of carbon coatin... more The paper presents the results of mechanical and tribological tests of two kinds of carbon coatings with advanced microstructures - nanocomposite CrC/a-C:H and multilayer TiN/Ti/a-C:H. The introduction of barriers for dislocation motion and microcrack propagation as CrC nanograins in nanocomposite coating or Ti and TiN interlayers in multilayer led to coatings hardening and improved fracture and wear resistance in comparison to a single amorphous a-C:H coating. It was confirmed by wide range of mechanical tests. The mechanism of microcrack deflection and splitting on CrC nanograins and Ti layers was studied using spherical indentation tests and TEM observations of indent cross-sections.
Microstructure characterization of an as deposited coating; (a) image obtained using SEM; (b) ima... more Microstructure characterization of an as deposited coating; (a) image obtained using SEM; (b) image done by TEM technique in STEM mode. Microstructure characterization of the coating at the cross-section, done by TEM; (a) TEM BF image; (b) STEM image.
ABSTRACT Development of a new generation of multilayer coatings as well as a microstructure under... more ABSTRACT Development of a new generation of multilayer coatings as well as a microstructure understanding of the mechanisms operating at the smallest length scale (nano- and atomic-scale) during wear, opens an avenue for the fabrication of future high-tech functional surfaces. Coatings for the presented work were fabricated by a pulsed laser deposition supported by magnetron sputtering. Microstructure characterization has been performed on as-deposited coatings as well as on coatings after mechanical wear test. Thin foils for detailed TEM microstructure observation were cut directly from the mechanically deformed area, using the FIB technique. Wear mechanisms operating at the small length scale of TiN/Ti/a-C:H multilayer coatings subjected to mechanical wear was studied by means of transmission electron microscopy (TEM). Cracking of the multilayer systems propagated layer by layer. The highest stress concentration during mechanical uploading was moved through the multilayer coating by breaking only one layer at the time.
Studies of advanced protective chromium‐based coatings on the carbon fibre composite (CFC) were p... more Studies of advanced protective chromium‐based coatings on the carbon fibre composite (CFC) were performed. Multidisciplinary examinations were carried out comprising: microstructure transmission electron microscopy (TEM, HREM) studies, micromechanical analysis and wear resistance. Coatings were prepared using a magnetron sputtering technique with application of high‐purity chromium and carbon (graphite) targets deposited on the CFC substrate. Selection of the CFC for surface modification in respect to irregularities on the surface making the CFC surface more smooth was performed. Deposited coatings consisted of two parts. The inner part was responsible for the residual stress compensation and cracking initiation as well as resistance at elevated temperatures occurring namely during surgical tools sterilization process. The outer part was responsible for wear resistance properties and biocompatibility. Experimental studies revealed that irregularities on the substrate surface had a negative influence on the crystallites growth direction. Chromium implanted into the a‐C:H structure reacted with carbon forming the cubic nanocrystal chromium carbides of the Cr23C6 type. The cracking was initiated at the coating/substrate interface and the energy of brittle cracking was reduced because of the plastic deformation at each Cr interlayer interface. The wear mechanism and cracking process was described in micro‐ and nanoscale by means of transmission electron microscope studies. Examined materials of coated CFC type would find applications in advanced surgical tools.
Carbon fiber structures provide strength, stiffness, and fatigue resistance. Carbon-based materia... more Carbon fiber structures provide strength, stiffness, and fatigue resistance. Carbon-based materials show, however, significant oxidative degradation in air beginning at temperatures in the region of 400 °C. Therefore, a coating concept for carbon–carbon composites consists of an inner part, which serves as a structural link with stress compensation ability to the carbon substrate, and an outer part, which acts as a diffusion barrier. In the presented paper, chromium/chromium nitride (Cr/CrN) multilayer structure has been selected as the inner part. The outer part of the coating, in the presented paper, was hydrogenated amorphous carbon (a-C:H). Among doping metals, Cr, as one of the carbide formed elements, possesses an attractive combination of properties (corrosion resistance, wear resistance, etc.). Thus, in the presented paper, a-C:H part of the coating was implanted by Cr nanocrystals. Coatings were deposited by means of magnetron sputtering technique. They were subjected to co...
Abstract Requirements for tribological protective coatings for medical tools, which would increas... more Abstract Requirements for tribological protective coatings for medical tools, which would increase their wear and corrosion resistance, are very high. The presented paper deals with novel nano-composite, multilayer protective coatings for tissue interaction elaboration and their diagnosis on metallic substrates. A hybrid pulsed laser deposition system was used for coating deposition. In the presented work, nano-composite Cr/CrN + [Cr/a-C : H implanted by metallic nanocrystals] multilayer coatings were developed for surface protection. The mechanical properties of the coatings were investigated by means of micro-hardness and elasticity modulus measurements. Bio-medical tests were conducted using eukaryotic cells. Microstructural analysis by means of transmission electron microscopy indicated that chromium which was implanted into a-C : H layers reacted with carbon forming chromium carbides.
Bioinspired, Biomimetic and Nanobiomaterials, 2014
The current work explains the influence of the polymer substrate on the topography formation of n... more The current work explains the influence of the polymer substrate on the topography formation of nano-wrinkled thin titanium films. Similar to the biomimetic antetype of human skin, this wrinkling phenomenon increases the elastic deformability of hard materials under tensile loading by flattening the wrinkled waves before high tensile stresses occur. Low energetic plasma deposition in direct current magnetron sputtering leads to smoother films with equiaxed domed wrinkle topography without a distinct preferred orientation on polymers (polyethylene terephthalate, polycarbonate, thermoplastic polyurethane). These domes are at least one order of magnitude larger than the commonly found topography on stiff silicon and correlates to the size of crystalline spherulites and segments in the applied semi- and pseudo-crystalline polymers. High energetic plasma deposition in pulsed laser deposition results in denser films with stretching of wrinkles. Higher intrinsic stresses require for relaxa...
Chromium carbonitride (CrCxN1−x) coatings are becoming more and more interesting for wear protect... more Chromium carbonitride (CrCxN1−x) coatings are becoming more and more interesting for wear protection applications due to their increased hardness and improved wear performance compared to chromium nitride (CrNx) hard coatings. Further improvements seem to be possible by using multilayer coatings of these two materials. In the current work such multilayer structures were deposited by the Pulsed Laser Deposition (PLD) technique
Multilayer Cr/CrN/Cr/Cr(N,C) and Cr/CrN with 8 and 32 layer coatings were deposited on austenite ... more Multilayer Cr/CrN/Cr/Cr(N,C) and Cr/CrN with 8 and 32 layer coatings were deposited on austenite substrates using pulsed laser deposition (PLD) technique. The microstructure observations were performed using Philips CM20trade mark, TECNAI G(2) F20 - TWINtrade mark and JEOL EX4000trade mark transmission microscopes. The performed experiments indicated that lowering the argon flow from 60 to 30 cm(3)/s during chromium ablation changes buffer layers microstructure from nearly amorphous to nano-crystalline. The nitride or carbo-nitride layers turned out to be less sensitive to changes in nitrogen flow during deposition. The columnar microstructure of Cr layers is coarser than those in CrN ones under the same deposition condition. This observation proved also that relying on PLD technique as thin as 30 nm layers might be formed within multilayer Cr/CrN coatings.
Archives of Civil and Mechanical Engineering, 2013
ABSTRACT This work is focused on the bio-inspired design of hard and tough multilayer coatings of... more ABSTRACT This work is focused on the bio-inspired design of hard and tough multilayer coatings of titanium (Ti) and titanium nitride (TiN) to reach both favourable mechanical and tribological behaviour. Biomimetic ideal is nacre, which is the inner layer of mollusk shell and both hard and tough. This combination of contrary material properties is due to its multilayered structure of thin aragonite tablets with dovetail geometry and nano-scaled protein binding interlayers. Transmission electron studies of the magnetron sputtered coatings on soft austenite substrate revealed either brittle behaviour of single layer TiN coatings (through-thickness cohesive coating fracture) or tough properties of multilayered structures (TiN layer fracture and Ti layer plastic deformation in deformation lines). The deformation mechanisms of Ti in between the TiN layers in the crack bands are result of strain hardening and separation of the crack edges in TiN: This broadens the deformation zone and prevents early fracture. The formed wave-like structure shows similar function as the dovetail-structure of aragonite tablets in nacre. Tribology in nacre is based on shearing of tablets. Wear in multilayered Ti–TiN structures is a result of cohesive film fracture and subsequent fatigue of the coating–substrate interface.
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