CN116443929A - High-entropy perovskite photochromic ceramic material and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of high-entropy perovskite ceramic materials, in particular to a high-entropy perovskite photochromic ceramic material and a preparation method thereof. The chemical general formula of the high-entropy perovskite photochromic ceramic material is ABO ₃ Wherein the A-site element is Ba element, and the B-site element is composed of five elements of Zr element, mg element, nb element, ta element, sn element, ti element and Zn element according to a mol ratio of 1:1:1:1:1. The invention designs the problems existing in the development of the prior high-entropy material in a targeted way and selects the ABO with a relatively stable structure ₃ The perovskite oxide utilizes various transition metal elements to carry out high entropy on the B site of the perovskite oxide, and the perovskite oxide successfully prepares the high entropy perovskite ceramic material with a stable single-phase structure, can generate obvious photochromism, and has important promotion effect on the development of the high entropy non-metal oxide material.

Description

A kind of high-entropy perovskite photochromic ceramic material and preparation method thereof

technical field

The invention relates to the technical field of high-entropy perovskite ceramic materials, in particular to a high-entropy perovskite photochromic ceramic material and a preparation method thereof.

Background technique

Generally, a mixture containing five or more elements in equiatomic ratio or near equiatomic ratio is defined as a high-entropy material. Compared with traditional materials, high-entropy materials have four unique effects, namely thermodynamic high-entropy effect, lattice distortion effect, kinetic retardation effect and performance "cocktail effect", thanks to its unique four effects , high-entropy materials show the advantages of a large space for component adjustment and strong adjustability of material properties, which make them have excellent performance and broad application prospects. In the past, most of the research on high-entropy materials focused on high-entropy alloys, and there were relatively few studies on high-entropy ceramic materials, and most of them chose structures such as shale, fluorite, pyrochlore, and spinel for high-entropy conversion. Based on these High-entropy ceramics with a structure are difficult to form single-phase substances, and most of them have obvious second or even third phases. Finding high-entropy ceramics with a new structure is an urgent problem to be solved in the development of high-entropy ceramics.

Contents of the invention

Based on the above, the present invention provides a high-entropy perovskite photochromic ceramic material and a preparation method thereof. The high-entropy perovskite photochromic ceramic material of the present invention can exhibit obvious photochromic phenomenon, and has mine structure.

To achieve the above object, the present invention provides the following scheme:

One of the technical solutions of the present invention is a high-entropy perovskite photochromic ceramic material with a general chemical formula of ABO ₃ , wherein the A-site element is Ba element, and the B-site element consists of Zr element, Mg element, Nb element, Ta element Five elements among the element, the Sn element, the Ti element and the Zn element are composed in a molar ratio of 1:1:1:1:1.

The ionic radii of the above-mentioned B-site elements are not much different in the case of 6 coordination, which reduces the difference in ionic size and is conducive to the synthesis of a stable single-phase structure, while the radii of Ca, Pb and other elements are too large to cause larger lattices. Distortion is not conducive to the formation of a stable single-phase structure.

The three elements of Zr/Nb/Ta meet the requirements of B-site ionic radius and valence. The three elements of Zr/Nb/Ta are resistant to high temperature and are not easy to volatilize. They can exist stably after high-temperature synthesis and support the formation of a stable single-phase structure. .

Further, the chemical formula is: Ba(Zr _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ , Ba(Zr _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ , Ba(Zr _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ or Ba(Zr _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ .

The second technical solution of the present invention is a method for preparing the above-mentioned high-entropy perovskite photochromic ceramic material, comprising the following steps:

Step 1, mixing and ball milling the metal carbonate and/or metal oxide corresponding to the constituent elements of the high-entropy perovskite photochromic ceramic material to obtain a mixed material;

Step 2, drying the mixed material to obtain high-entropy perovskite ceramic powder;

Step 3, calcining the high-entropy perovskite ceramic powder to obtain the high-entropy perovskite photochromic ceramic material.

Further, in step 1, the ball milling is specifically wet ball milling, and the grinding aid solvent is distilled water and/or absolute ethanol; the time of the ball milling is 12-48 hours.

Preferably, the grinding aid solvent is absolute ethanol. Absolute ethanol is non-toxic and harmless and has good volatility, which can improve the dispersibility of raw materials during ball milling and is more conducive to the mixing of raw materials.

Further, in step 2, the temperature of the drying treatment is 50-150° C., and the time is 18-36 hours.

Further, in step 3, the calcination is two-stage calcination, specifically: the first-stage calcination, calcination at 1200-1300° C. for 3-9 hours; the second-stage calcination, 1300-1450° C. calcination for 3-9 hours.

The purpose of the first stage of calcination is to make the carbonate discharge carbon dioxide and moisture in the raw materials in a high-temperature environment to prevent pores and cracks in the later sintering process, and melt and mix various raw materials until a crystallized powder precursor is obtained.

The purpose of the second stage of calcination is to evacuate the organic matter to increase the density, and to refine the grains in a high-temperature environment to obtain a high-entropy perovskite photochromic ceramic material with regular grain shapes and sizes.

The heating and cooling rates of the above two stages of calcination are: heating up 4°C/min and cooling down 5°C/min.

Below the above-mentioned calcination temperature range, the porcelain-forming effect is poor or even not porcelain-forming, which will affect the photochromic performance. Above the above-mentioned temperature range, the sample will show greater brittleness and will cause bending of the sample, which will also affect the photochromic performance. Therefore In the present invention, the calcination temperature of the first stage is preferably limited to 1200-1300°C, and the calcination temperature of the second stage is 1300-1450°C.

If the heating rate is too high, the various elements in the sample cannot be well integrated, which is not conducive to the synthesis of a single-phase structure and the uniform distribution of various elements. If the heating rate is too low, the heating rate is too slow to waste energy;

If the cooling rate is too high, the cooling rate is too fast, and various elements inside the sample will segregate and the sample will crack. Therefore, the present invention preferably limits the temperature rise and fall rates of the two-stage calcination to be: temperature rise 4°C/min, temperature fall 5°C/min.

Further, after the first stage of calcination, the steps of grinding and pressing are also included.

The pressure of the press molding is 10-15 MPa, and it is pressed into a circular flake.

Further, after the second stage of calcination, steps of polishing and ultrasonic cleaning are also included.

The purpose of polishing and ultrasonic cleaning is to facilitate the later test, wherein the polishing, grinding and cleaning processes all adopt methods well known to those skilled in the art.

The third technical solution of the present invention is the application of the above-mentioned high-entropy perovskite photochromic ceramic material in the fields of storage and anti-counterfeiting.

The fourth technical solution of the present invention is a photochromic anti-counterfeiting material, comprising the above-mentioned high-entropy perovskite photochromic ceramic material.

The invention discloses the following technical effects:

The structural stability of the ABO ₃ type perovskite oxide is better than other structures, and the structural collapse is not easy to occur after high entropy, and the structural stability can still be maintained, which can ensure that the synthesized sample is a single-phase substance; The problems existing in the development of high-entropy materials were designed specifically, and ABO _3- type perovskite oxides with relatively stable structures were selected, and a variety of transition metal elements and alkaline earth metal elements were used to high-entropy the B-site, and successfully prepared The discovery of high-entropy perovskite ceramic materials with a stable single-phase structure plays an important role in promoting the development of high-entropy non-metal oxide materials.

Due to the presence of more metal elements in high-entropy materials, there is a large lattice distortion inside the material, which is conducive to the generation of more defects inside the material. This feature is used to control the composition of the material to obtain a material that can occur High-entropy perovskite ceramic materials with apparent photochromism.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is an X-ray diffraction spectrum of the high-entropy perovskite photochromic ceramic material prepared in Examples 1-4 of the present invention.

Fig. 2 is the scanning electron microscope (SEM) figure of the high-entropy perovskite photochromic ceramic material prepared by the embodiment of the present invention 1～4; Wherein, (a) is embodiment 1, (b) is embodiment 2, ( c) is Example 3, and (d) is Example 4.

Fig. 3 is an element distribution (EDS) diagram of the high-entropy perovskite photochromic ceramic material prepared in Example 2 of the present invention.

Fig. 4 is the photochromic photograph of the high-entropy perovskite photochromic ceramic material prepared by Example 4 of the present invention; wherein, (a) is a photo when photochromic phenomenon does not occur; (b) is 365nm light irradiation 0.5 The photo of the sample after photochromic phenomenon occurred after s; (c) is the photo of the sample after photochromic phenomenon occurred after 365nm light irradiation for 120s; (d) is the photo of the sample without photochromic phenomenon and after 365nm light irradiation for 120s Comparison photographs after photochromism occurs.

Figure 5 shows the surface reflectance of the high-entropy perovskite photochromic ceramic materials prepared in Examples 1-4 of the present invention at room temperature, the surface reflectance after being irradiated with a 365nm laser for 120s, and the surface reflection after being heated at 250°C for 60s Rate spectrogram; Wherein, (a) is embodiment 1, (b) is embodiment 2, (c) is embodiment 3, (d) is embodiment 4.

Detailed ways

Various exemplary embodiments of the present invention will now be described in detail. The detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features and embodiments of the present invention.

It should be understood that the terminology described in the present invention is only used to describe specific embodiments, and is not used to limit the present invention. In addition, regarding the numerical ranges in the present invention, it should be understood that each intermediate value between the upper limit and the lower limit of the range is also specifically disclosed. Any stated value or intervening value in a stated range, and each smaller range between any other stated value or intervening value in a stated range, is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded from the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only the preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and/or materials in connection with which the documents are described. In case of conflict with any incorporated document, the contents of this specification control.

It will be apparent to those skilled in the art that various modifications and changes can be made in the specific embodiments of the present invention described herein without departing from the scope or spirit of the present invention. Other embodiments will be apparent to the skilled person from the description of the present invention. The description and examples of the invention are illustrative only.

As used herein, "comprising", "comprising", "having", "comprising" and so on are all open terms, meaning including but not limited to.

The "room temperature" mentioned in the present invention means 15-30°C unless otherwise specified.

The raw materials used in the examples of the present invention can be obtained through commercially available channels unless otherwise specified.

The source and purity of the raw materials used in the examples of the present invention are shown in Table 1.

Table 1

raw material name Manufacturer purity BaCO ₃ Aladdin Reagent (Shanghai) Co., Ltd. 99% _ZrO2 Aladdin Reagent (Shanghai) Co., Ltd. 99.99% MgO Sinopharm Chemical Reagent Co., Ltd. ≥99% Nb ₂ O ₅ Aladdin Reagent (Shanghai) Co., Ltd. 99.9% Ta ₂ O ₅ Aladdin Reagent (Shanghai) Co., Ltd. 99.99% _SnO2 Sinopharm Chemical Reagent Co., Ltd. ≥99.5% TiO ₂ Aladdin Reagent (Shanghai) Co., Ltd. 99% ZnO Aladdin Reagent (Shanghai) Co., Ltd. 99%

Example 1

A kind of chemical formula is: Ba(Zr _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ high-entropy perovskite photochromic ceramic material, the preparation steps are as follows:

Step 1: Weigh the raw materials BaCO ₃ , ZrO ₂ , MgO, and Nb ₂ according to the molar ratio of Ba element, Zr element, Mg element, Nb element, Ta element, and Sn element in a ratio of 5:1:1:1:1:1. O ₅ , Ta ₂ O ₅ , SnO ₂ ; put them together with absolute ethanol in a ball mill jar for 24 hours to obtain a mixed material.

Step 2: transfer the mixed material obtained in step 1 to an ordinary glass beaker with a straw, and place it in an electric constant temperature blast drying oven at 90° C. for 24 hours to obtain a high-entropy perovskite ceramic powder.

Step 3, performing two-stage calcination on the high-entropy perovskite ceramic powder obtained in step 2;

The first stage of calcination: put the high-entropy perovskite ceramic powder in a corundum crucible, put it into a muffle furnace, and heat it up from room temperature to 1300°C at a heating rate of 4°C/min for 6 hours, and then heat it up at a cooling rate of 5°C/min Cool down to room temperature to obtain a powder precursor; put the powder precursor in an agate mortar and grind until it becomes a finer powder without obvious particles, transfer it to a tableting mold, and apply a pressure of 10Mpa to obtain a regular shape Round flakes with flat surface;

The second stage of calcination: the above-mentioned circular flakes are placed in a muffle furnace and calcined from room temperature to 1400 °C at a heating rate of 4 °C/min for 6 hours, and then cooled to room temperature at a cooling rate of 5 °C/min to obtain a round Flake-shaped high-entropy perovskite ceramic material; the surface is polished and polished by common polishing powder to obtain a round ceramic sheet with a flat and smooth surface. In order to remove the polishing powder and other impurities on the surface, it is ultrasonically Cleaning to obtain a high-entropy perovskite photochromic ceramic material with a smooth and clean surface and a chemical formula of Ba(Zr _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ .

Example 2

A kind of chemical formula is: Ba(Zr _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ high-entropy perovskite photochromic ceramic material, the preparation steps are as follows:

Step 1: Weigh the raw materials BaCO ₃ , ZrO ₂ , MgO, and Nb ₂ according to the molar ratio of Ba element, Zr element, Mg element, Nb element, Ta element, and Ti element in a ratio of 5:1:1:1:1:1. O ₅ , Ta ₂ O ₅ , TiO ₂ ; put them together with absolute ethanol in a ball mill jar and mill them for 24 hours to obtain a mixed material.

Step 2: transfer the mixed material obtained in step 1 to an ordinary glass beaker with a straw, and place it in an electric constant temperature blast drying oven at 90° C. for 24 hours to obtain a high-entropy perovskite ceramic powder.

Step 3, performing two-stage calcination on the high-entropy perovskite ceramic powder obtained in step 2;

The first stage of calcination: put the high-entropy perovskite ceramic powder in a corundum crucible, put it in a muffle furnace, and heat it up from room temperature to 1300°C for 6 hours at a heating rate of 4°C/min, and then cool it down at a rate of 5°C/min Reduce the speed to room temperature to obtain a powder precursor; put the powder precursor in an agate mortar and grind until it becomes a finer powder with no obvious particles, transfer it to a tableting mold, and apply a pressure of 10Mpa to obtain a shape Round flakes with regular and flat surfaces;

The second stage of calcination: the above-mentioned circular flakes are placed in a muffle furnace and calcined from room temperature to 1400 °C at a heating rate of 4 °C/min for 6 hours, and then cooled to room temperature at a cooling rate of 5 °C/min to obtain a round Flake-shaped high-entropy perovskite ceramic material; the surface is polished and polished by common polishing powder to obtain a round ceramic sheet with a flat and smooth surface. In order to remove the polishing powder and other impurities on the surface, it is ultrasonically Cleaning to obtain a high-entropy perovskite photochromic ceramic material with a smooth and clean surface and a chemical formula of Ba(Zr _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ .

Example 3

A kind of chemical formula is: Ba(Zr _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ high-entropy perovskite photochromic ceramic material, the production steps are as follows:

Step 1: Weigh the raw materials BaCO ₃ , ZrO ₂ , ZnO, and Nb ₂ according to the molar ratio of Ba element, Zr element, Zn element, Nb element, Ta element, and Sn element in a ratio of 5:1:1:1:1:1. O ₅ , Ta ₂ O ₅ , SnO ₂ ; put them together with absolute ethanol in a ball mill jar for 24 hours to obtain a mixed material.

Step 2: transfer the mixed material obtained in step 1 to an ordinary glass beaker with a straw, and place it in an electric constant temperature blast drying oven at 90° C. for 24 hours to obtain a high-entropy perovskite ceramic powder.

Step 3, performing two-stage calcination on the high-entropy perovskite ceramic powder obtained in step 2;

The first stage of calcination: put the high-entropy perovskite ceramic powder in a corundum crucible, put it in a muffle furnace, and heat it up from room temperature to 1300°C for 6 hours at a heating rate of 4°C/min, and then cool it down at a rate of 5°C/min Reduce the speed to room temperature to obtain a powder precursor; put the powder precursor in an agate mortar and grind until it becomes a finer powder with no obvious particles, transfer it to a tableting mold, and apply a pressure of 10Mpa to obtain a shape Round flakes with regular and flat surfaces;

The second stage of calcination: the above-mentioned circular flakes are placed in a muffle furnace and calcined from room temperature to 1400 °C at a heating rate of 4 °C/min for 6 hours, and then cooled to room temperature at a cooling rate of 5 °C/min to obtain a round Flake-shaped high-entropy perovskite ceramic material; the surface is polished and polished by common polishing powder to obtain a round ceramic sheet with a flat and smooth surface. In order to remove the polishing powder and other impurities on the surface, it is ultrasonically Cleaning to obtain a high-entropy perovskite photochromic ceramic material with a smooth and clean surface and a chemical formula of Ba(Zr _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ .

Example 4

A kind of chemical formula is: Ba(Zr _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ high-entropy perovskite photochromic ceramic material, the production steps are as follows:

Step 1: Weigh the raw materials BaCO ₃ , ZrO ₂ , ZnO, and Nb ₂ according to the molar ratio of Ba element, Zr element, Zn element, Nb element, Ta element, and Ti element in a ratio of 5:1:1:1:1:1. O ₅ , Ta ₂ O ₅ , TiO ₂ ; put them together with absolute ethanol in a ball mill jar and mill them for 24 hours to obtain a mixed material.

Step 2: transfer the mixed material obtained in step 1 to an ordinary glass beaker with a straw, and place it in an electric constant temperature blast drying oven at 90° C. for 24 hours to obtain a high-entropy perovskite ceramic powder.

Step 3, performing two-stage calcination on the high-entropy perovskite ceramic powder obtained in step 2;

The first stage of calcination: put the high-entropy perovskite ceramic powder in a corundum crucible, put it in a muffle furnace, and heat it up from room temperature to 1300°C for 6 hours at a heating rate of 4°C/min, and then cool it down at a rate of 5°C/min Reduce the speed to room temperature to obtain a powder precursor; put the powder precursor in an agate mortar and grind until it becomes a finer powder with no obvious particles, transfer it to a tableting mold, and apply a pressure of 10Mpa to obtain a shape Round flakes with regular and flat surfaces;

The second stage of calcination: the above-mentioned circular flakes are placed in a muffle furnace and calcined from room temperature to 1400 °C at a heating rate of 4 °C/min for 6 hours, and then cooled to room temperature at a cooling rate of 5 °C/min to obtain a round Flake-shaped high-entropy perovskite ceramic material; the surface is polished and polished by common polishing powder to obtain a round ceramic sheet with a flat and smooth surface. In order to remove the polishing powder and other impurities on the surface, it is ultrasonically Cleaning to obtain a high-entropy perovskite photochromic ceramic material with a smooth and clean surface and a chemical formula of Ba(Zr _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ .

Performance Testing:

(1) X-ray diffraction experiment:

X-ray diffraction experiments were performed on the high-entropy perovskite photochromic ceramic materials (samples) prepared in Examples 1-4, and XRD diffraction patterns corresponding to each example were obtained.

Fig. 1 is the X-ray diffraction spectrum of the high-entropy perovskite photochromic ceramic material diffraction angle 20～80 ° that embodiment 1～4 prepares; The diffraction peaks of 4 samples correspond well to BaSnO ₃ (PDF15-0780) standard card , there is no obvious second phase, and the synthesized samples are pure phase substances, indicating that the samples have successfully achieved high entropy, indicating that the technical solution based on the present invention can realize the preparation of high entropy perovskite ceramic materials, and can maintain a stable Pure phase structure, through analysis, it is known that all four samples belong to stable cubic phase structure. As can be found from Fig. 1, compared with the samples prepared by Examples 2 and 4, the positions of the diffraction peaks of the samples prepared by Examples 1 and 3 are shifted to small angles, because Sn ²⁺ (CN=8, ) has an ionic radius greater than that of Ti ²⁺ (CN=8, /> ).

(2) Scanning electron microscope experiment:

2 is a scanning electron microscope (SEM) image of the high-entropy perovskite photochromic ceramic material prepared in Examples 1-4. Shown in (a), (b), (c) and (d) in Fig. 2 is the scanning electron microscope (SEM) of the high-entropy perovskite photochromic ceramic material (sample) that embodiment 1～4 prepares successively As shown in Fig. 4, the surfaces of the 4 samples are flat and smooth without obvious holes, and the crystal grains are arranged regularly in sequence, showing greater compactness; the surface grains of the samples prepared in Example 1 and the samples prepared in Example 3 are relatively flat Plate shape, the sample surface crystal grain prepared by embodiment 2 and the sample prepared by embodiment 4 are fine spherical; Know that the crystal grain surface of the sample prepared by embodiment 1 and the sample prepared by embodiment 3 have fine cracks through analysis, It shows that the brittleness of the sample is relatively large; and the grain size of the sample prepared in Example 1 and the sample prepared in Example 3 is relatively large, both of which are caused by the high sintering temperature, which will promote the crystal grain size. The secondary crystallization of grains leads to an increase in crystal size, and at the same time increases the brittleness of ceramics and reduces the toughness of ceramics, indicating that Ti element is more resistant to high temperature than Sn element.

(3) Element distribution (EDS) experiment:

Fig. 3 is an element distribution (EDS) diagram of the high-entropy perovskite photochromic ceramic material (sample) prepared in Example 2 of the present invention. As shown in (a) in Fig. 3, select and carry out elemental distribution analysis in the partial region of sample prepared by embodiment 2, (b), (c), (d), (e), (f), (g) in Fig. 3 ), (h) are the distribution of Ba element, Zr element, Mg element, Nb element, Ta element, Ti element, and O element in the selected area of the sample in turn. Through analysis, it is found that 7 elements are evenly distributed in this area. There is no obvious element segregation, indicating that the synthesized sample is a high-entropy perovskite ceramic material; some black areas can be seen in the distribution diagram of the seven elements, which is because the grains in the selected area are not arranged at the same height. There are some height differences, which lead to some blind spots in the probe scanning process, so it shows a black area. The above conclusions show that the preparation of high-entropy perovskite ceramic materials can be realized based on the technical solution of the present invention.

(4) Photochromic phenomenon experiment:

Fig. 4 is the photochromic photograph of the high-entropy perovskite photochromic ceramic material (sample) prepared in embodiment 4; Among Fig. 4 (a) is the photograph when the whole sample surface prepared in embodiment 4 is not irradiated by light , (b) in Fig. 4 is the photo of some samples in the sample prepared in Example 4 after being irradiated by light of 365nm wavelength for 0.5s at room temperature, (c) in Fig. 4 is in the sample prepared in Example 4 Photos of some samples after being irradiated by light with a wavelength of 365nm for 120s at room temperature, (d) in Figure 4 is the color comparison between the part of the sample prepared in Example 4 that was irradiated with light with a wavelength of 365nm for 120s and the part that was not irradiated by light Photo.

From Figure 4 (a), it can be seen that the surface of the sample not irradiated by 365nm wavelength light is light yellow, and from Figure 4 (b), it can be seen that the surface of the sample irradiated by 365nm wavelength light for 0.5s is light brown , indicating that the sample undergoes rapid photochromic phenomenon under the irradiation of light with a wavelength of 365nm, and at the same time shows a more obvious color transition on the surface of the sample. The surface of the sample is dark brown. From Figure 4 (d), it can be seen that the color contrast of the sample before and after being irradiated with 365nm wavelength light for 120s is extremely obvious, indicating that the sample can exhibit obvious photoinduced Discoloration phenomenon.

(5) Photochromic performance experiment:

Fig. 5 is the surface reflectance of the high-entropy perovskite photochromic ceramic material (sample) prepared in Examples 1 to 4 at room temperature, the surface reflectance after being irradiated with a 365nm laser for 120s, and the surface after being heated at 250°C for 60s Reflectance spectrogram; (a), (b), (c) and (d) in Fig. 5 correspond to the reflectance spectrogram of the sample prepared by embodiment 1～4 successively, and three lines in each figure correspond respectively successively:

(1) Initial state: test the reflectance spectrum of the sample at room temperature;

(2) Irradiation state: 4 samples were placed under light with a wavelength of 365nm and irradiated for 120s at room temperature, and then the reflectance spectrum was tested;

(3) Recovery state: place the sample in a heating environment at 250°C for 60 seconds, and then place it in a room temperature environment to cool after heating, and test the reflectance spectrum after the sample is cooled;

It can be clearly seen from Figure 5 that after the sample is irradiated with light of 365nm wavelength for 120s, the reflectance of the sample surface drops sharply, and the reflectance of the sample surface returns to initial state. The reflectance of the samples prepared in Examples 2 and 4 changed relatively large before and after irradiation, indicating that the samples with Ti ⁴⁺ participation were more conducive to the excellent photochromic performance of the samples than the Sn ⁴⁺ participation. The four samples all showed excellent reversible photochromic properties, indicating that the technical solution based on the present invention can realize the preparation of high-entropy perovskite ceramic materials, and utilize the characteristic that there are many defects inside the high-entropy material to determine its composition. The adjustment made the samples exhibit more prominent photochromic properties.

The present invention proposes a new high-entropy perovskite ceramic material with a new principal component, and successfully synthesizes a high-entropy perovskite photochromic ceramic material with a stable single-phase structure through a high-temperature solid-state method, further targeting its physical and chemical properties Designed to exhibit pronounced photochromism. The invention realizes the preparation of a single-phase novel high-entropy perovskite photochromic ceramic material.

The above-mentioned embodiments are only to describe the preferred mode of the present invention, and are not intended to limit the scope of the present invention. Variations and improvements should fall within the scope of protection defined by the claims of the present invention.

Claims (10)

1. A high-entropy perovskite photochromic ceramic material is characterized in that the chemical formula is ABO ₃ Wherein the A-site element is Ba element, and the B-site element is composed of five elements of Zr element, mg element, nb element, ta element, sn element, ti element and Zn element according to a mol ratio of 1:1:1:1:1.

2. The high entropy perovskite photochromic ceramic material of claim 1 wherein the chemical formula is: ba (Zr) _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ 、Ba(Zr _0.2 Mg _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ 、Ba(Zr _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Sn _0.2 )O ₃ Or Ba (Zr) _0.2 Zn _0.2 Nb _0.2 Ta _0.2 Ti _0.2 )O ₃ 。

3. A method of preparing the high entropy perovskite photochromic ceramic material of claim 1 or 2, comprising the steps of:

step 1, mixing and ball milling metal carbonate and/or metal oxide corresponding to the constituent elements of the high-entropy perovskite photochromic ceramic material to obtain a mixed material;

step 2, drying the mixed material to obtain high-entropy perovskite ceramic powder;

and step 3, calcining the high-entropy perovskite ceramic powder to obtain the high-entropy perovskite photochromic ceramic material.

4. The preparation method according to claim 3, wherein in the step 1, the ball milling is specifically wet ball milling, and the auxiliary milling solvent is distilled water and/or absolute ethyl alcohol; the ball milling time is 12-48 h.

5. The method according to claim 3, wherein in the step 2, the drying treatment is performed at a temperature of 50 to 150 ℃ for 18 to 36 hours.

6. A method according to claim 3, wherein in step 3, the calcination is a two-stage calcination, specifically: first-stage calcination, wherein the calcination is carried out for 3-9 hours at 1200-1300 ℃; and the second stage of calcination, namely, the calcination is carried out for 3 to 9 hours at 1300 to 1450 ℃.

7. The method according to claim 6, further comprising the steps of grinding and press forming after the first calcination.

8. The method according to claim 6, further comprising polishing and ultrasonic cleaning steps after the second stage calcination.

9. Use of a high entropy perovskite photochromic ceramic material according to claim 1 or 2 in the field of storage and anti-counterfeiting.

10. A photochromic anti-counterfeiting material comprising the high-entropy perovskite photochromic ceramic material of claim 1 or 2.