Sheet-like perovskite structure high-entropy ceramic powder and preparation method thereof

Abstract

A kind of sheet perovskite structure high-entropy ceramic powder and preparation method thereof, material components are designed by tolerance factor t, SrCO3, BaCO3, CaCO3, La2O3, PbO, Bi2O3 and TiO2 are used as raw materials to prepare high-entropy sheet perovskite structure (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3, (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 powder material by two-step molten salt method.The prepared high-entropy sheet perovskite structure powder provides template seed crystal for preparing high-entropy sheet perovskite textured ceramic using template grain growth technology.Due to the "high-entropy effect" under the cooperation of multiple components and special morphology, unique electrical and thermal properties can be obtained.The raw materials of the present application are easy to obtain, the medium used is salt, and the difficulty or pollution to the environment caused by the subsequent treatment is not caused by the difficulty or pollution to the environment caused by the subsequent treatment.In addition, the present application has the characteristics of simple process, easy-to-control process parameters and easy industrialization, and the obtained powder has good and stable sheet morphology.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of powder preparation technology in inorganic non-metallic material science, and particularly relates to a flaky perovskite structure high-entropy ceramic powder of (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 (M = La or Pb) and a preparation method thereof. BACKGROUND

[0002] High-entropy ceramics are a kind of entropy-stable equimolar or near-equimolar multi-component single-phase solid solution. The concept of high-entropy materials was first proposed in 2004 to describe equimolar high-entropy alloys. Research has found that high-temperature smelting of equimolar or near-equimolar multiple alloy elements is easy to form a single-phase solid solution with a simple crystal structure and random atomic distribution, which can prevent the formation of intermetallic compounds and display a typical "high-entropy effect" by maximizing configurational entropy. Since five metal oxides were first reported as raw materials for designing high-entropy oxide ceramics in 2015, the research on high-entropy ceramics has been continuously expanding, covering multiple structural types and non-oxide materials, and exhibiting multiple excellent properties including high dielectric constant, super ionic conductivity and the like, indicating its wide application potential in the fields of thermoelectric conversion, thermal barrier coating, catalyst and the like. The remarkable characteristics of high-entropy ceramics are derived from its inherent "high-entropy effect", which ensures the stability of the single phase of the material under extreme environmental conditions and exhibits excellent phase stability in various application scenarios. In the crystal structure of high-entropy ceramics, multiple elements coexist in specific lattice sites, causing significant mass, strain and volume fluctuations, which in turn lead to the introduction of disordered phonon scattering and point defects. Related research shows that as the entropy value of the system increases, the disordered scattering of phonons also increases, while the dipole moment, polarization strength and lattice thermal conductivity of the material decrease, which is beneficial to the optimization of the thermoelectric performance.

[0003] In the field of thermoelectric material research, in addition to the introduction of high-entropy components to enhance performance, the construction of textured ceramics is also considered as a key strategy to improve the thermoelectric performance. Through precise control of crystal orientation, the texturing process can guide the grains to preferentially orient along a certain direction, thereby forming significant anisotropy in the material. Research shows that the anisotropy can be enhanced to improve the electrical conductivity in a specific direction and significantly improve the power factor. Therefore, the combination of high-entropy and texturing strategies is considered to be able to decouple the electrical conductivity and thermal conductivity of thermoelectric ceramics, achieve the synergistic optimization of high electrical conductivity and low thermal conductivity, and improve the thermoelectric figure of merit.

[0004] In high-entropy ceramic materials with perovskite structure, multiple cations share lattice positions. Due to the differences in the radii and valence of these cations, they and oxygen ions O 2-The bonding characteristics between the atoms also change, leading to difficulty in controlling the phase composition and morphology. Therefore, how to obtain high-entropy perovskite seed crystal powder with large aspect ratio and sheet-like morphology is a very challenging research work. In recent years, various ceramic texture technologies have been developed, including heat treatment texture technology, non-equi-axial particle orientation solidification technology, strong magnetic field orientation technology, template grain growth technology, etc. In particular, the template grain growth technology and the reaction template grain growth technology have become the preferred method for preparing textured ceramics because of their simple process and easy scale production. In order to obtain high-texture degree textured ceramics, first of all, a precursor with obvious anisotropy characteristics needs to be prepared as a seed crystal. At present, the synthesis of high-entropy perovskite structure ceramic powder mainly depends on the solid phase method, which usually produces small, uniform and equiaxed particles, lacking the required anisotropy of morphology. In addition, researchers have also tried various synthesis routes such as sol-gel method, co-precipitation method and sol-hydrothermal method to prepare such powders. However, due to the high symmetry of the perovskite structure, the traditional preparation method generally faces the problems of lack of obvious anisotropy of powder morphology, small particle size and particle agglomeration, which restricts the texture design of high-entropy perovskite ceramics.

[0005] In the paper High Configuration Entropy Activated Lattice Oxygen for O2 Formation on Perovskite Electrocatalyst published in Advanced Functional Materials in 2022, volume 32, issue 28, Lina Tang et al. prepared high-entropy perovskite structure ceramic powder (La 0.6 Sr 0.4 )(Co 0. 2[FeMnNiMg] 0.8 )O3 with an average particle size of about 40 nm using the sol-gel method, which has a near-spherical particle morphology. It does not meet the requirements of anisotropic morphology and large aspect ratio, and is not suitable for use as a template seed powder for growing textured ceramics.

[0006] In the paper Advanced High Entropy Perovskite Oxide Electrocatalyst for Oxygen Evolution Reaction published in Advanced Functional Materials, Vol. 31, No. 27, 2021, Thi Xuyen Nguyen et al. prepared high-entropy perovskite oxide ceramic powders with the chemical formula La(CrMnFeCo2Ni)O3 and an average particle size of about 100 nm using the co-precipitation method. The morphology of the powders is amorphous agglomerated nanoparticles, which is not suitable for use as template seed crystal powders for growing textured ceramics.

[0007] In the paper Preparation of high entropy(Ba 0.2 Mg 0.2 Ca 0.2 Sr 0.2 Pb 0.2 )TiO3 perovskite oxide powders by a sol-hydrothermal method published in Ceramics International, Vol. 48, No. 11, 2022, Pengfei Yu et al. prepared high-entropy perovskite oxide ceramic powders with the chemical formula(Ba 0.2 Mg 0.2 Ca 0.2 Sr 0.2 Pb 0.2 )TiO3 and an average particle size of about 1 μm using the sol-hydrothermal method. The morphology of the powders is cubic block-shaped particles, which is not suitable for use as template seed crystal powders for the template grain growth technique.

[0008] Bismuth-layered oxide Bi4Ti3O 12 is composed of pseudo-perovskite layers [Bi2Ti3O 10 ] 2- and Bi2O2 2+ layers arranged alternately along the c-axis direction. The ab-plane growth resistance is small, and the growth resistance along the c-axis direction is large. Under the traditional preparation method, it has a flaky morphology, so it is a good precursor for preparing flaky high-entropy perovskite materials. Studies have shown that it is feasible to convert the precursor with similar structure into flaky perovskite ceramic powders by topological chemical microcrystal transformation using a two-step molten salt method.

[0009] In the paper Enhanced Electrical Conductivity of(001)Oriented Sr0.9 La 0.1 TiO3 Microplatelets forThermoelectric Applications, Zhang Ping and Gao Feng et al. prepared (001) oriented plate-like perovskite ceramic Sr 0.9 La 0.1 TiO3 with average particle size of about 9.62 μm and diameter-thickness ratio of 20, which is a good textured template seed crystal. However, the element design of high entropy is not involved, and the morphology control of plate-like high-entropy perovskite powder is not involved.

[0010] Northwest University disclosed a kind of medium high-entropy plate-like MBi4Ti4O 15 Powder material and preparation method thereof, Gao Feng et al. prepared medium high-entropy powder MBi4Ti4O 15 Powder material by molten salt method, with radial size of 0.5-5 μm and thickness of 0.1-0.5 μm, which is a good textured template seed crystal. Textured ceramic can be prepared by template growth method, including the preparation of ATiO3 based textured ceramic (A refers to four or more high-entropy element components). However, for the synthesis of perovskite structure textured ceramic, the seed crystal as a heterogeneous precursor induces the reaction of texture in the process of template growth method, and the product ceramic contains the heterogeneous precursor, which is not the optimal choice of seed crystal. For the synthesis of perovskite structure textured ceramic, the most suitable precursor should be plate-like high-entropy perovskite structure ceramic powder with the same chemical structure.

[0011] In summary, the high-entropy perovskite powder prepared by the current research is mostly amorphous morphology, and there is no report on plate-like morphology with large diameter-thickness ratio. At the same time, the research of plate-like perovskite powder is mostly focused on low-entropy ceramic or non-pure perovskite ceramic, and the research of plate-like high-entropy pure perovskite structure ceramic powder has not been reported. SUMMARY

[0012] In order to overcome the deficiency that it is difficult to prepare plate-like perovskite structure high-entropy ceramic powder in the prior art, the present application provides a plate-like perovskite structure high-entropy ceramic powder and a preparation method thereof.

[0013] The preparation method is to use two-step molten salt method process to prepare plate-like (Ca 12 Sr 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 (M=La or Pb) high-entropy ceramic powder material by in-situ topological microcrystal transformation.

[0014] The high-entropy plate-like (Ca 0.25Sr 0.25 Ba 0.25 M 0.25 )TiO3(M=La or Pb) powder material is characterized in that the morphology is a high-entropy component perovskite structure powder material in a sheet shape, and the chemical composition is CSBLT or CSBPT. 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3; the CSBPT is (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3.

[0015] The raw material of the precursor Bi4Ti3O 12 is Bi2O3 and TiO2, each of which is of analytical purity and micron grade, and the TiO2 is of rutile structure.

[0016] The raw material for generating the (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 is CaCO3, SrCO3, BaCO3, La2O3 and Bi4Ti3O 12 , each of which is of analytical purity and micron grade. The Bi4Ti3O 12 is prepared from Bi2O3 and TiO2 by a molten salt method.

[0017] The raw material for generating the (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 is CaCO3, SrCO3, BaCO3, PbO and Bi4Ti3O 12 , each of which is of analytical purity and micron grade. The Bi4Ti3O 12 is prepared from Bi2O3 and TiO2 by a molten salt method.

[0018] The specific process for preparing the sheet-shaped (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 (M=La or Pb) high-entropy ceramic powder material is as follows:

[0019] Step 1, preparing the precursor Bi4Ti3O 12 :

[0020] The precursor Bi4Ti3O12 The specific process is as follows:

[0021] I. Measuring raw materials:

[0022] When calculating the proportion of raw materials for preparing Bi4Ti3O 12 , the amount of Bi2O3 added is increased by 7.5wt% on the basis of atomic composition, and the raw materials Bi2O3 and TiO2 are measured according to the proportion.

[0023] II. Preparing raw material-salt mixed powder:

[0024] The measured Bi4Ti3O 12 raw materials are placed in a polytetrafluoroethylene ball mill tank, and NaCl-KCl mixed salt with a molar ratio of 1:2 to the raw materials is added. The NaCl-KCl mixed salt is a mixture of NaCl and KCl with a molar ratio of 1:1.

[0025] ZrO balls and anhydrous ethanol are added to the polytetrafluoroethylene ball mill tank. The polytetrafluoroethylene ball mill tank is placed in a ball mill at a rotation speed of 240 r / min for 24 h.

[0026] The amount of ZrO balls added is 2.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials. The amount of anhydrous ethanol added is also 2.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials.

[0027] The raw material-salt mixed powder required for preparing Bi4Ti3O 12 is obtained.

[0028] III. Calcination

[0029] The raw material-salt mixed powder required for preparing Bi4Ti3O 12 is calcined in a high-temperature box-type resistance furnace to obtain a mixed product containing two substances, one being a flaky Bi4Ti3O 12 material, and the other being a NaCl-KCl salt block.

[0030] During calcination, the high-temperature box-type resistance furnace is raised to 1000℃ at a heating rate of 5℃ / min and maintained at this temperature for 8 h; after the holding period ends, it is cooled to 600℃ at a cooling rate of 5℃ / min; and it is cooled to room temperature with the furnace.

[0031] The NaCl-KCl salt block is a block-shaped substance formed from the NaCl-KCl mixed salt added to the raw materials before calcination that has not been volatilized completely.

[0032] IV. Washing:

[0033] The obtained NaCl-KCl salt block and Bi4Ti3O 12The mixture was washed to obtain the washed powder.

[0034] During the cleaning process, the obtained NaCl-KCl salt block is mixed with Bi4Ti3O 12 The mixture was placed in a beaker, 400 mL of deionized water was added, and the beaker was covered with plastic wrap. The beaker was placed in an oven and soaked for 48 hours, then the supernatant was poured off. After pouring off the supernatant, another 400 mL of deionized water was added, and the beaker was placed in a magnetic stirrer and stirred magnetically for 5 hours to pulverize the product. After pulverization, 400 mL of deionized water was repeatedly added to the NaCl-KCl salt block and Bi₄Ti₃O₃. 12 The mixture was washed and filtered until no Cl- was detected in the supernatant using AgNO3 reagent. - .

[0035] V-drying:

[0036] The cleaned powder was dried in an oven to obtain flake-shaped Bi4Ti3O. 12 Powder materials.

[0037] The bismuth layered oxide Bi4Ti3O 12 Composed of pseudo-perovskite layer [Bi2Ti3O] 10 ] 2- and Bi2O2 2+ The layers are arranged alternately along the c-axis, with greater growth resistance along the c-axis and less growth resistance on the ab-side, resulting in a sheet-like morphology.

[0038] The Bi4Ti3O 12 The radial dimensions of the powder range from 3.79 μm to 26.86 μm, the thickness ranges from 0.27 μm to 0.61 μm, and the aspect ratio is 25.04.

[0039] Step 2, Preparation of high-entropy ceramic powder with a plate-like perovskite structure:

[0040] Flake-shaped (Ca) were prepared by molten salt method. 0.25 Sr 0.25 Ba 0.25 M 0.25 TiO3 (M = La or Pb) high-entropy ceramic powder:

[0041] Ⅰ Weigh the raw materials:

[0042] In the preparation of CSBLT, CaCO3, SrCO3, BaCO3, and La2O3 were weighed according to their atomic stoichiometric ratios, and Bi4Ti3O3 prepared in step 1 was weighed according to the ratio (Ca+Sr+Ba+La):Bi = 10:4. 12 Precursor powder.

[0043] In preparing CSBPT, CaCO3, SrCO3, BaCO3 and PbO are weighed according to the stoichiometric ratio of atomic composition, and the Bi4Ti3O12 prepared in step 1 is weighed according to the ratio of (Ca+Sr+Ba+Pb):Bi=10:4. 12 The precursor powder.

[0044] II. Preparation of raw material-salt mixed powder

[0045] The weighed raw material of CSBLT or CSBPT is put into a polytetrafluoroethylene ball mill jar, and NaCl-KCl mixed salt is added in a molar ratio of 11:78 to the raw material; the NaCl-KCl mixed salt is a mixture of NaCl and KCl in a molar ratio of 1:1.

[0046] ZrO balls and anhydrous ethanol are added to the polytetrafluoroethylene ball mill jar. The polytetrafluoroethylene ball mill jar is placed in a ball mill for ball milling at a speed of 300 r / min for 24 h.

[0047] The amount of ZrO balls added is 2.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw material. The amount of anhydrous ethanol added is also 2.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw material.

[0048] The raw material-salt mixed powder required for preparing CSBLT or the raw material-salt mixed powder required for preparing CSBPT is obtained.

[0049] III. Calcination:

[0050] The raw material-salt mixed powder required for preparing CSBLT or the raw material-salt mixed powder required for preparing CSBPT is calcined in a high-temperature box-type resistance furnace to obtain a product of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 mixed with NaCl-KCl salt blocks and by-product Bi2O3, or a product of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 mixed with NaCl-KCl salt blocks and by-product Bi2O3.

[0051] During calcination, the high-temperature box-type resistance furnace is raised to a temperature of 900-1100°C at a rate of 5°C / min and maintained at this temperature for 4 h; after the end of the holding period, the temperature is lowered to 600°C at a rate of 5°C / min; and the furnace is cooled to room temperature.

[0052] The NaCl-KCl salt blocks are block-shaped substances formed from the NaCl-KCl mixed salt added to the raw material before calcination and not volatilized.

[0053] The by-product Bi2O3 is Bi2O3 in the precursor during the calcination process 3+ and Bi2O2 2+ The granular material is converted from the removed layer.

[0054] IV. Washing with water:

[0055] The obtained (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 mixed with NaCl-KCl salt block, or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 mixed with NaCl-KCl salt block is washed to obtain the washed powder.

[0056] The washing is performed by putting the obtained (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 mixed with NaCl-KCl salt block and by-product Bi2O3, or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 mixed with NaCl-KCl salt block and by-product Bi2O3 into a beaker, adding 400 mL of deionized water and covering with a plastic wrap. The beaker is placed in an oven for soaking, and then filtered and crushed. Deionized water is added again and placed in a magnetic stirrer. The product is repeatedly washed and filtered by magnetic stirring for 5 h until no Cl - is detected in the upper clear liquid obtained by using AgNO3 reagent, proving that the NaCl-KCl salt block has been removed.

[0057] V. Acid washing:

[0058] The obtained (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 mixed with by-product Bi2O3, or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 mixed with by-product Bi2O3 is washed with HNO3 solution to obtain the washed powder.

[0059] The washing is performed by putting the obtained (Ca 0.25 Sr 0.25 Ba 0.25La 0.25 )TiO3 mixed with by-product Bi2O3, or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 mixed with by-product Bi2O3 into a beaker, 400 mL of deionized water is added, and 80 mL of concentrated nitric acid with a concentration of 65-68% is added, the beaker is placed in a magnetic stirrer and stirred for 20 min, after stirring is completed, 400 mL of deionized water is added again and stirred for 40 min, and then 400 mL of deionized water is added again and stirred for 60 min.

[0060] VI drying:

[0061] The obtained washed powder is placed in an oven for drying to obtain a high-entropy flaky MTiO3 powder material.

[0062] The CSBLT or CSBPT inherits the flaky morphology of the precursor Bi4Ti3O 12 The bismuth layer oxide Bi4Ti3O 12 is composed of pseudo-perovskite layers [Bi2Ti3O 10 ] 2- and Bi2O2 2+ layers arranged alternately along the c-axis direction, and has a large growth resistance along the c-axis direction and a small growth resistance on the ab plane, and has a flaky morphology. During the calcination process of step 2, Ca 2+ , Sr 2+ , Ba 2 + , La 3+ , or Ca 2+ , Sr 2+ , Ba 2+ , Pb 2+ substitutes Bi 3+ in the pseudo-perovskite layer into the cation site of the perovskite structure, and Bi 3+ and Bi2O2 2+ layers in the precursor are removed and converted into by-product Bi2O3 granular material during the calcination process, which is removed by acid washing.

[0063] The (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 powder has a radial size of 2.24 μm to 10.22 μm, a thickness of 0.10 μm to 0.41 μm, and a ratio of diameter to thickness of 21.39 to 22.58. The (Ca 0.25 Sr 0.25 Ba 0.25 Pb0.25 The radial size of the TiO3 powder is 1.48-17.55 mu m, the thickness is 0.04-0.90 mu m, and the ratio of the radial size to the thickness is 12.03-15.31.

[0064] The present application aims to prepare high-entropy sheet perovskite structure powder, and provide a template seed crystal for preparing high-entropy sheet perovskite textured ceramic by using a template grain growth technique.

[0065] The present application designs material components by a tolerance factor t, and uses a two-step molten salt method to prepare high-entropy sheet perovskite structure (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3, (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 powder material by taking CaCO3, SrCO3, BaCO3, La2O3, PbO, Bi2O3 and TiO2 as raw materials.

[0066] Compared with the prior art, the present application has the following beneficial effects:

[0067] The present application prepares two kinds of high-entropy sheet perovskite structure ceramic powders with the chemical formula (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 (M=La or Pb): (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 and (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3.

[0068] In the Bi4Ti3O 12 product prepared by the molten salt method, the layered oxide [Bi2Ti3O 10 ] 2- and Bi2O2 2+ layers are alternately arranged along the c-axis direction to form a larger growth resistance along the c-axis direction, and the molten salt liquid phase enhances the transmission rate, so that the sheet morphology is more easily obtained. The perovskite structure powder MTiO3 is converted through topological microcrystal transformation, takes the pseudo-perovskite layer structure [Bi2Ti3O 10 ] 2- as a template, and grows to obtain a layered perovskite structure in a molten salt environment through ion exchange.

[0069] By Figure 1 X-ray diffraction pattern of the final synthetic product obtained at a calcination temperature of 900 DEG C is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 with a pure perovskite structure. Figure 2 X-ray diffraction pattern of the final synthetic product obtained at a calcination temperature of 900 DEG C to 1100 DEG C is (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 powder with a pure perovskite structure; in addition, the (00l) diffraction peak in the pattern is sharp, indicating that the powder particles have undergone preferred growth. Figure 3 Scanning electron microscope (SEM) photos of the prepared (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 powder show that the powder has a uniform size distribution and good dispersibility, with a radial size of 2.24 μm to 10.22 μm, a thickness of 0.10 μm to 0.41 μm, and a radial thickness ratio of 21.39 to 22.58. Figure 3 Scanning electron microscope (SEM) photos of the prepared (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 powder show that the powder has a uniform size distribution and good dispersibility, with a radial size of 1.48 μm to 17.55 μm, a thickness of 0.04 μm to 0.90 μm, and a radial thickness ratio of 12.03 to 15.31. Figure 5 6 Transmission electron microscope (TEM) energy dispersive spectroscopy (EDS) of the prepared flaky powder shows that the elements Ba, Sr, Ca, La and Ba, Sr, Ca, Pb are uniformly distributed in the powder, and there is no segregation; point analysis shows that each element enters the product lattice.The present application fills the research gap of flaky high-entropy perovskite powder. At the same time, the raw materials in the present application are easy to obtain, the medium used is salt, and water, which is easy to dissolve, will not bring difficulties or pollution to the post-processing; in addition, the present application has the characteristics of simple process, easy-to-control process parameters and easy industrialization, and the obtained powder has good and stable flaky morphology. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1 X-ray diffraction pattern of the prepared (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3.

[0071] Figure 2 The (Ca) obtained in this invention 0.25 Sr 0.25 Ba 0.25 Pb 0.25 X-ray diffraction pattern of TiO3.

[0072] Figure 3 (Ca) after calcination at 900℃ for 8 hours 0.25 Sr 0.25 Ba 0.25 La 0.25 Scanning electron microscope image of TiO3.

[0073] Figure 4 (Ca) after calcination at 900℃ for 8 hours 0.25 Sr 0.25 Ba 0.25 Pb 0.25 Scanning electron microscope image of TiO3.

[0074] Figure 5 These are transmission electron microscope images and EDS elemental distributions of the product; among which:

[0075] 5a is the obtained (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 High-angle annular dark-field image of TiO3;

[0076] 5b is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 Distribution diagram of Ca element in TiO3;

[0077] 5c is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 Distribution diagram of Sr element in TiO3;

[0078] 5d is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 Ba element distribution diagram in TiO3;

[0079] 5e is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 La elemental distribution diagram in TiO3;

[0080] 5f is (Ca 0.25Sr 0.25 Ba 0.25 La 0.25 Ti element distribution map in (Ca

[0081] 5g is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 O element distribution map in (Ca

[0082] Figure 6 transmission electron micrograph and EDS element distribution of the product; wherein:

[0083] 6a is a high-angle annular dark-field image of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3;

[0084] 6b is a Ca element distribution map in (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3;

[0085] 6c is a Sr element distribution map in (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3;

[0086] 6d is a Ba element distribution map in (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3;

[0087] 6e is a Pb element distribution map in (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3;

[0088] 6f is a Ti element distribution map in (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3;

[0089] 6g is an O element distribution map in (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3;

[0090] Figure 7A schematic diagram of the technical solution of the present application.

[0091] Figure 8 A flow chart of the present application.

[0092] Figure: 1 is the standard card PDF #89-4934 of SrTiO3; 2 is the X-ray diffraction pattern of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 after calcination at 900℃ for 8h; 3 is the X-ray diffraction pattern of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 after calcination at 1000℃ for 4h; 4 is the X-ray diffraction pattern of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 after calcination at 1100℃ for 2h; 5 is the standard card PDF #89-4934 of SrTiO3; 6 is the X-ray diffraction pattern of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 after calcination at 900℃ for 8h; 7 is the X-ray diffraction pattern of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 after calcination at 1000℃ for 4h; 8 is the X-ray diffraction pattern of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 after calcination at 1100℃ for 2h. DETAILED DESCRIPTION

[0093] The present application is a perovskite structure powder material with high-entropy component and flaky morphology, which will be described in detail through six examples.

[0094] The molar ratio of the chemical composition of the high-entropy component flaky powder material is (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3, wherein M = La or Pb.

[0095] When M = La, the chemical composition of the high-entropy component flaky powder material is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25)TiO3, abbreviated as CSBLT.

[0096] When M=Pb, the chemical composition of the high-entropy component flaky powder material is (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3, abbreviated as CSBPT.

[0097] The (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 precursor is Bi4Ti3O 12 . The raw materials of the precursor are Bi2O3 and TiO2, and the molar ratio of Bi2O3 to TiO2 is 2.1886:3. Both Bi2O3 and TiO2 used as precursor raw materials are analytically pure, and the particle size is micron grade. The TiO2 is rutile structure. For the convenience of description, the Bi4Ti3O 12 is abbreviated as BTO.

[0098] The raw materials for generating the (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 are CaCO3, SrCO3, BaCO3, La2O3 and Bi4Ti3O 12 . Each of the raw materials is analytically pure, and the particle size is micron grade. The Bi4Ti3O 12 is prepared by a molten salt method from Bi2O3 and TiO2. For the convenience of description, the (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 is abbreviated as CSBLT.

[0099] The raw materials for generating the (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 are CaCO3, SrCO3, BaCO3, PbO and Bi4Ti3O 12 , and each of the raw materials is analytically pure, and the particle size is micron grade. The Bi4Ti3O 12 is prepared by a molten salt method from Bi2O3 and TiO2. For the convenience of description, the (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 is abbreviated as CSBPT.

[0100] The amounts of the raw materials are shown in Table 1.

[0101] Table 1 shows the amounts of the raw materials and the salt in each example.

[0102]

[0103] The preparation method of the present application is a two-step molten salt method process for preparing a precursor powder Bi4Ti3O 12 The present application relates to a method for preparing a flaky (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 high-entropy ceramic powder material by in-situ topotactic microcrystal conversion. The present application will be described in detail through six examples.

[0104] The present application provides a method for preparing a flaky (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 high-entropy ceramic powder material. The specific process is as follows:

[0105] Step 1: preparing a precursor Bi4Ti3O 12 :

[0106] I. Measuring the raw materials:

[0107] Bi2O3 and TiO2 are measured according to the molar ratio. The amount of TiO2 is the same as the titanium content in (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3.

[0108] II. Preparing the raw material-salt mixed powder:

[0109] The measured Bi2O3 and TiO2 raw materials are placed in a polytetrafluoroethylene ball mill jar, and NaCl-KCl mixed salt is added, and the molar ratio of Bi2O3 and TiO2 raw materials to the NaCl-KCl mixed salt is 1:2.

[0110] The NaCl-KCl mixed salt is a mixture composed of NaCl and KCl, and the molar ratio of NaCl to KCl is 1:1.

[0111] ZrO balls and anhydrous ethanol are continuously added to the polytetrafluoroethylene ball mill jar. The polytetrafluoroethylene ball mill jar is placed in a ball mill for ball milling at a speed of 240 r / min for 24 h. The reactant mixed powder of Bi4Ti3O 12 is obtained.

[0112] The ZrO ball is added in an amount of 2.0 times the sum of the mass of the raw materials. 12 The ZrO ball is added in an amount of 2.0 times the sum of the mass of the raw materials. 12 The ZrO ball is added in an amount of 1.5 times the sum of the mass of the raw materials.

[0113] III Calcination:

[0114] The raw material-salt mixed powder is calcined in a high-temperature box-type resistance furnace to obtain flaky Bi4Ti3O 12 The mixture of the precursor material and the NaCl-KCl salt block.

[0115] During the calcination, the high-temperature box-type resistance furnace is raised to 1000°C at a temperature raising rate of 5°C / min and kept at this temperature for 8h; after the end of the temperature keeping, the temperature is lowered to 600°C at a temperature lowering rate of 5°C / min; and the furnace is cooled to room temperature.

[0116] The NaCl-KCl salt block is a block-shaped substance formed by the NaCl-KCl mixed salt added in the raw materials before calcination and not volatilized.

[0117] IV Washing:

[0118] The obtained Bi4Ti3O 12 The mixture of the precursor material and the NaCl-KCl salt block is washed to obtain the washed powder.

[0119] During the washing, the obtained mixture of the NaCl-KCl salt block and Bi4Ti3O 12 is placed in a beaker, deionized water is added and the mixture is submerged.

[0120] The beaker is covered with a plastic wrap and is placed in a 60°C oven for soaking, so that the NaCl-KCl salt block is dissolved in the deionized water. After 48h of soaking, the supernatant is poured out. After the supernatant is poured out, the same amount of deionized water is added again and the mixture is submerged. The beaker is placed in a magnetic stirrer, and the product is crushed by magnetic stirring for 5h. After the end of the crushing, the deionized water is repeatedly added and washed and filtered until no Cl - is detected in the obtained supernatant by AgNO3 reagent. The washing of the mixture of the Bi4Ti3O 12 precursor material and the NaCl-KCl salt block is completed.

[0121] V Drying:

[0122] The obtained washed powder is placed in a 60°C oven for drying for 24h to obtain flaky Bi4Ti3O 12 precursor.

[0123] The Bi4Ti3O 12 The process parameters are shown in Table 2.

[0124] Table 2 Process parameters for preparing Bi4Ti3O 12 in step 1 by the molten salt method

[0125]

[0126]

[0127] In the present application, the precursor Bi4Ti3O 12 is obtained through calcination, cleaning and drying. The unit cell structure of the precursor Bi4Ti3O 12 is composed of pseudo-perovskite layers [Bi2Ti3O 10 ] 2- and Bi2O2 2+ layers arranged alternately along the c-axis direction, which has a large growth resistance along the c-axis direction and a small growth resistance on the ab plane, and has a sheet-like morphology.

[0128] The precursor Bi4Ti3O 12 has a radial size of 3.79-26.86 μm and a thickness of 0.27-0.61 μm, and a radial thickness ratio of 25.04.

[0129] Step 2, preparation of a sheet-like perovskite high-entropy ceramic powder:

[0130] Preparation of a high-entropy sheet-like ceramic powder (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 by the molten salt method:

[0131] The high-entropy sheet-like ceramic powder (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 )TiO3 is CSBLT or CSBPT.

[0132] When the CSBLT is prepared, the specific process is as follows:

[0133] I. Weigh the raw materials:

[0134] When the CSBLT is prepared, CaCO3, SrCO3, BaCO3 and La2O3 are weighed according to the stoichiometric ratio of the element composition of the CSBLT. The precursor Bi4Ti3O 12 is weighed according to the sum of the mass of the weighed CaCO3, SrCO3, BaCO3 and La2O3. The precursor Bi4Ti3O 12The amount of the raw material-salt mixed powder is calculated according to the molar ratio of (CaCO3+SrCO3+BaCO3+La2O3) : Bi4Ti3O 12 = 6:1 ~ 12:1. The (CaCO3+SrCO3+BaCO3+La2O3) : Bi4Ti3O 12 = 6:1 ~ 12:1 is denoted as A: BTO = 6:1 ~ 12:1.

[0135] II. Preparation of raw material-salt mixed powder:

[0136] The weighed CaCO3, SrCO3, BaCO3, La2O3 and Bi4Ti3O 12 As raw materials, they are put together in a polytetrafluoroethylene ball mill tank, and NaCl-KCl mixed salt is added, and the molar ratio of the raw materials to the NaCl-KCl mixed salt is 11:38 ~ 11:118.

[0137] The NaCl-KCl mixed salt is composed of NaCl and KCl with a molar ratio of 1:1.

[0138] ZrO balls and anhydrous ethanol are added to the polytetrafluoroethylene ball mill tank. The polytetrafluoroethylene ball mill tank is placed in a ball mill at a rotation speed of 200 ~ 500 r / min for 12 ~ 48 h.

[0139] The amount of the ZrO balls added is 1.0 ~ 3.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials. The amount of the anhydrous ethanol added is 1.0 ~ 3.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials.

[0140] The raw material-salt mixed powder required for the preparation of CSBLT is obtained.

[0141] III. Calcination:

[0142] The obtained raw material-salt mixed powder is poured into an alumina crucible, covered with a crucible cover, and placed in a box-type resistance furnace. The box-type resistance furnace is raised to 900 ~ 1100℃ at a temperature rising rate of 5 ~ 15℃ / min and kept at this temperature for 2 ~ 8 h; after the heat preservation is completed, it is cooled to 500 ~ 700℃ at a cooling rate of 5 ~ 15℃ / min; and the furnace is cooled to room temperature, and the calcination is completed.

[0143] Through calcination, a product of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 mixed with NaCl-KCl salt and by-product Bi2O3 is obtained.

[0144] The NaCl-KCl salt block is the block-shaped substance formed by the incomplete volatilization of the NaCl-KCl mixed salt added to the raw material before calcination. The by-product Bi2O3 is the granular substance formed by the removal of the Bi2O3 layer converted from the Bi2O3 layer in the precursor during the calcination process. 3+ and Bi2O2 2+ layer is removed and converted into a granular substance.

[0145] IV. Water washing:

[0146] During the water washing, the mixed product of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 and the NaCl-KCl salt block and the by-product Bi2O3 is placed in a beaker, deionized water is added, and the deionized water is used to immerse the mixed product.

[0147] Plastic wrap is used to prevent the deionized water from evaporating in the oven. The beaker is placed in a 60-90°C oven for immersion, so that the salt block is dissolved in the deionized water. After 48h of immersion, the supernatant is poured out. After the supernatant is poured out, deionized water is added again, and the deionized water is used to immerse the mixed product; the beaker is placed in a magnetic stirrer, the stirring speed is 200-500r / min, and the product is crushed by magnetic stirring for 4-6h to obtain a crushed mixed product.

[0148] After the crushing is completed, deionized water is repeatedly added to the obtained crushed mixed product to repeatedly wash and filter the product of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 mixed with the NaCl-KCl salt block and the by-product Bi2O3, until no Cl - is detected in the obtained supernatant by AgNO3 reagent. After the water washing is completed, a mixed product of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 and the by-product Bi2O3, from which the NaCl-KCl salt block is removed, is obtained.

[0149] V. Acid washing:

[0150] The mixed product of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 and the by-product Bi2O3 is placed in a beaker and placed in a magnetic stirrer, and a nitric acid solution with a concentration of 25% is added.

[0151] According to the (Ca 0.25 Sr0.25 Ba 0.25 La 0.25 )TiO3 of 5g (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 corresponds to 265mL nitric acid solution.

[0152] The mixed product of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 and by-product Bi2O3 is stirred magnetically for 20 min. After the first stirring, the stirring and washing with deionized water are repeated, and the stirring and washing time for each is 20 min. The total stirring time during the pickling process is 2h. After the stirring, the washing with deionized water is repeated until the upper clear liquid in the beaker is not detected with AgNO3 solution. The pickling is completed, and the CSBLT powder from which the by-product Bi2O3 is removed is obtained. -

[0153] VI drying:

[0154] The obtained powder from which the by-product Bi2O3 is removed is placed in a 60℃ oven for drying for 24h, and the high-entropy sheet perovskite structure powder material CSBLT is obtained.

[0155] When the CSBPT is prepared, the specific process is as follows:

[0156] I. weighing raw materials:

[0157] The raw materials include CaCO3, SrCO3, BaCO3 and PbO, and Bi4Ti3O 12 precursor.

[0158] In the preparation of CSBPT, CaCO3, SrCO3, BaCO3 and PbO are weighed according to the stoichiometric ratio (molar ratio) of the element composition of the CSBPT. The precursor Bi4Ti3O 12 is weighed according to the sum of the mass of the weighed CaCO3, SrCO3, BaCO3 and PbO. The amount of the weighed precursor Bi4Ti3O 12 is calculated according to the molar ratio of (CaCO3+SrCO3+BaCO3+PbO):Bi4Ti3O 12 =6:1~12:1. (CaCO3+SrCO3+BaCO3+PbO):Bi4Ti3O 12 =6:1~12:1 is recorded as A:BTO=6:1~12:1.

[0159] ​II. Preparation of raw material-salt mixed powder:

[0160] The weighed CaCO3, SrCO3, BaCO3, PbO and Bi4Ti3O 12 As raw materials, the NaCl-KCl mixed salt was added into a polytetrafluoroethylene ball mill jar, and the molar ratio of the raw materials to the NaCl-KCl mixed salt was 11:38-11:118.

[0161] The NaCl-KCl mixed salt was made of NaCl and KCl with a molar ratio of 1:1.

[0162] ZrO balls and anhydrous ethanol were added into the polytetrafluoroethylene ball mill jar. The polytetrafluoroethylene ball mill jar was placed in a ball mill for 12-48 h at a rotation speed of 200-500 r / min.

[0163] The amount of the ZrO balls added was 1.0-3.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials. The amount of the anhydrous ethanol added was 1.0-3.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials.

[0164] The raw material-salt mixed powder required for the preparation of CSBPT was obtained.

[0165] III. Calcination:

[0166] The obtained raw material-salt mixed powder was poured into an alumina crucible, and a crucible cover was put on. The crucible was placed in a box-type resistance furnace. The furnace was heated to 900-1100 °C at a heating rate of 5 °C / min, and the temperature was kept for 2-8 h. After the temperature keeping, the furnace was cooled to 500-700 °C at a cooling rate of 5-15 °C / min. The furnace was cooled to room temperature, and the calcination was completed.

[0167] Through calcination, a product of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 )TiO3 mixed with NaCl-KCl salt blocks and by-product Bi2O3 was obtained.

[0168] The NaCl-KCl salt blocks were block-shaped substances formed by the NaCl-KCl mixed salt added into the raw materials before calcination and not volatilized completely. The by-product Bi2O3 was a granular substance formed by the removal and conversion of the Bi 3+ and Bi2O2 2+ layers in the precursor during the calcination process.

[0169] IV. Water washing:

[0170] During the water washing, the obtained (Ca 0.25 Sr0.25 Ba 0.25 Pb 0.25 The mixture of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3 and NaCl-KCl salt block and by-product Bi2O3 is put into a beaker, deionized water is added, and the deionized water is used to immerse the mixture.

[0171] A plastic wrap is used to prevent the deionized water from evaporating in the oven. The beaker is placed in a 60-90°C oven for immersion, so that the salt block is dissolved in the deionized water. After 48h of immersion, the supernatant is poured out. After the supernatant is poured out, deionized water is added again, and the deionized water is used to immerse the mixture. The mixture is washed and filtered.

[0172] The beaker is placed in a magnetic stirrer, and the stirring speed is 200-500r / min. The washed and filtered mixture is crushed by magnetic stirring for 4-6h.

[0173] The crushed mixture is repeatedly immersed in deionized water, so that the (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3 and NaCl-KCl salt block and by-product Bi2O3 are repeatedly washed and filtered until no Cl - is detected in the supernatant obtained by using AgNO3 reagent, and the washing is completed to obtain a mixture of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3 and by-product Bi2O3 without NaCl-KCl salt block.

[0174] V. Acid washing:

[0175] The obtained mixture of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3 and by-product Bi2O3 is put into a beaker and placed in a magnetic stirrer, and a nitric acid solution with a concentration of 25% is added.

[0176] The amount of nitric acid is determined according to the mass of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3; specifically, 5g of (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3 corresponds to 265mL of nitric acid solution.

[0177] For the addition of nitric acid solution (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The mixture of TiO3 and the byproduct Bi2O3 was magnetically stirred for 20 minutes. After the first stirring, deionized water was repeatedly added for stirring and washing, with each stirring and washing session lasting 20 minutes. The total stirring time during the acid washing process was 2–6 hours. After stirring, deionized water was repeatedly added for washing until no Cl- could be detected in the supernatant of the beaker with AgNO3 solution. This completed the acid washing process, yielding CSBPT powder with the byproduct Bi2O3 removed.

[0178] VI. Drying:

[0179] The obtained powder with Bi2O3 removed byproduct was dried in an oven at 60℃ for 24 hours to obtain high-entropy sheet-like perovskite structure powder material CSBPT.

[0180] Table 3 Process parameters for each embodiment in step 2.

[0181]

[0182] The process parameters for each embodiment are detailed in Table 3.

[0183] In this invention, after calcination, cleaning, and drying, the CSBLT or CSBPT utilizes topological microcrystal transformation to inherit the precursor Bi4Ti3O. 12 The flaky morphology of bismuth layered oxide Bi₄Ti₃O₃. 12 Composed of pseudo-perovskite layer [Bi2Ti3O] 10 ] 2- and Bi2O2 2+ The layers are arranged alternately along the c-axis, with greater growth resistance along the c-axis and less growth resistance on the ab-plane, resulting in a lamellar morphology. During the calcination process in step 2, Ca... 2+ 、Sr 2+ Ba 2+ La 3+ or Ca 2+ 、Sr 2+ Ba 2+ Pb 2+ Bi replacing the pseudo-perovskite layer 3+ The cation sites that enter the perovskite structure, and the Bi in the precursor during calcination. 3+ and Bi2O2 2+ The layer is removed and transformed into Bi2O3 particulate matter as a byproduct, which is then removed by acid washing. Due to the liquid phase environment provided by molten salt at high temperature, the atomic diffusion rate is accelerated, resulting in better plate-like morphology, larger radial dimensions, and a higher aspect ratio for perovskite prepared by the molten salt method.

[0184] The scanning electron microscope photos of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 prepared by the present application are shown in the following figures. As can be seen from the scanning electron microscope photos, the (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO3 powder prepared by the present application has a uniform size distribution, good dispersibility, and obvious flaky morphology, with a diameter of 1 μm to 4 μm and a thickness of 0.1 μm to 0.3 μm. Figure 3

[0185] The size of the powder obtained in each example is shown in Table 4.

[0186] Table 4 Size of the powder of the product of each example

[0187] ​

Claims

1. A high-entropy ceramic powder with a lamellar perovskite structure, characterized in that, The molar ratio of the chemical components is (Ca 0.25 Sr 0.25 Ba 0.25 M 0.25 TiO3, where M = La or Pb; When M=La, the chemical composition of the high-entropy component sheet-like powder material is (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 TiO3, abbreviated as CSBLT; When M=Pb, the chemical composition of the high-entropy component plate-like powder material is (Ca... 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3, abbreviated as CSBPT; The (Ca) 0.25 Sr 0.25 Ba 0.25 M 0.25 The precursor of TiO3 is Bi4Ti3O 12 The Bi4Ti3O 12 Abbreviated as BTO; the precursor is made from Bi2O3 and TiO2, and the molar ratio of Bi2O3 to TiO2 is 2.1886:3; the TiO2 has a rutile structure; A two-step molten salt process was used to process Bi4Ti3O precursor powder. 12 In-situ topological microcrystal transformation to prepare sheet-like (Ca) 0.25 Sr 0.25 Ba 0.25 M 0.25 TiO3 (M=La or Pb) is a high-entropy ceramic powder material.

2. The high-entropy ceramic powder with a lamellar perovskite structure as described in claim 1, characterized in that, Generate the (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 The raw materials for TiO3 are CaCO3, SrCO3, BaCO3, La2O3, and Bi4Ti3O. 12 The Bi4Ti3O 12 Prepared from Bi₂O₃ and TiO₂ via a molten salt method; the (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 TiO3 is abbreviated as CSBLT.

3. The high-entropy ceramic powder with a lamellar perovskite structure as described in claim 1, characterized in that, Generate the (Ca) 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The raw materials for TiO3 are CaCO3, SrCO3, BaCO3, PbO, and Bi4Ti3O. 12 All the raw materials mentioned are analytical grade and have a particle size in the micrometer range; the Bi4Ti3O 12 Prepared from Bi₂O₃ and TiO₂ via a molten salt method; the (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3 is abbreviated as CSBPT.

4. A method for preparing the plate-like perovskite structure high-entropy ceramic powder of claim 1, characterized in that, The specific process is as follows: Step 1: Preparation of precursor Bi4Ti3O by molten salt method 12 : By calcining the raw material-salt mixed powder, flaky Bi4Ti3O was obtained. 12 A mixture of precursor materials and NaCl-KCl salt blocks; Step 2: Preparation of high-entropy plate-like ceramic powder (Ca) by molten salt method 0.25 Sr 0.25 Ba 0.25 M 0.25 TiO3: The high-entropy sheet-like ceramic powder (Ca) 0.25 Sr 0.25 Ba 0.25 M 0.25 TiO3 is either CSBLT or CSBPT; By preparing high-entropy sheet-like ceramic powder (Ca) 0.25 Sr 0.25 Ba 0.25 M 0.25 The TiO3 process includes preparing raw material-salt mixed powder, calcination, water washing, acid washing, and drying; resulting in high-entropy lamellar perovskite structure powder material CSBLT or high-entropy lamellar perovskite structure powder material CSBPT.

5. The method for preparing plate-like perovskite structured high-entropy ceramic powder as described in claim 4, characterized in that, Preparation of precursor Bi4Ti3O by molten salt method 12 The specific process is as follows: Ⅰ Weigh the raw materials: Weigh Bi₂O₃ and TiO₂ according to their molar ratio; the amount of TiO₂ used is related to the amount of (Ca) 0.25 Sr 0.25 Ba 0.25 M 0.25 The titanium content in TiO3 is the same; II. Preparation of raw material-salt mixed powder: Weigh the Bi2O3 and TiO2 raw materials and put them into a polytetrafluoroethylene ball mill jar. Add NaCl-KCl mixed salt and make the molar ratio of Bi2O3 and TiO2 raw materials to the NaCl-KCl mixed salt 1:

2. The NaCl-KCl mixed salt is a mixture of NaCl and KCl; the molar ratio of NaCl to KCl is 1:

1. ZrO balls and anhydrous ethanol were added to the polytetrafluoroethylene ball mill jar; the PTFE ball mill jar was then placed in a ball mill and milled at 240 r / min for 24 h to obtain Bi4Ti3O. 12 The reactant mixture powder; The amount of ZrO spheres added is equal to the mass of the NaCl-KCl mixed salt and the mass of Bi₄Ti₃O₂. 12 The amount of anhydrous ethanol added is 2.0 times the sum of the raw material masses; the amount of anhydrous ethanol added is the sum of the masses of the NaCl-KCl mixed salt and Bi4Ti3O. 12 1.5 times the sum of the raw material masses; III. Calcination: The raw material-salt mixed powder was calcined in a high-temperature box-type resistance furnace to obtain flaky Bi4Ti3O. 12 A mixture of precursor materials and NaCl-KCl salt blocks; During the calcination process, the high-temperature box-type resistance furnace is heated to 1000℃ at a heating rate of 5℃ / min and maintained at this temperature for 8 hours; after the holding period, the temperature is lowered to 600℃ at a cooling rate of 5℃ / min; and then cooled to room temperature along with the furnace. The NaCl-KCl salt block is a blocky substance formed from the unevaporated NaCl-KCl mixed salt added to the raw materials before calcination; IV. Cleaning: The obtained Bi4Ti3O 12 The mixture of precursor material and NaCl-KCl salt block is washed to obtain washed powder. V Drying: The cleaned powder was dried in a 60 °C oven for 24 h to obtain flake-like Bi4Ti3O. 12 Precursor.

6. The method for preparing plate-like perovskite structured high-entropy ceramic powder as described in claim 5, characterized in that, The precursor Bi4Ti3O 12 The radial dimensions range from 3.79 μm to 26.86 μm, the thickness ranges from 0.27 μm to 0.61 μm, and the aspect ratio is 25.

04.

7. The method for preparing plate-like perovskite structured high-entropy ceramic powder as described in claim 4, characterized in that, The specific process for preparing the CSBLT or CSBPT in step 2 is as follows: i. Weighing raw materials: In the preparation of CSBLT, the raw materials are CaCO3, SrCO3, BaCO3, and La2O3, as well as Bi4Ti3O. 12 Precursor; weigh CaCO3, SrCO3, BaCO3, and La2O3 according to the stoichiometric ratio of the CSBLT elemental composition; weigh the precursor Bi4Ti3O. 12 The dosage is based on (CaCO3+SrCO3+BaCO3+La2O3):Bi4Ti3O 12 Calculate the molar ratio of (CaCO3+SrCO3+BaCO3+La2O3):Bi4Ti3O3. 12 =6:1~12:1 is denoted as A:BTO=6:1~12:1; In preparing CSBPT, the raw materials are CaCO3, SrCO3, BaCO3, PbO, and Bi4Ti3O. 12 Precursor; In the preparation of CSBPT, CaCO3, SrCO3, BaCO3, and PbO are weighed according to the molar ratio of the elemental composition of the CSBPT; the precursor Bi4Ti3O is weighed according to the sum of the masses of CaCO3, SrCO3, BaCO3, and PbO. 12 The weighed precursor Bi4Ti3O 12 The dosage is based on (CaCO3+SrCO3+BaCO3+PbO):Bi4Ti3O 12 Calculate the molar ratio of (CaCO3+SrCO3+BaCO3+PbO):Bi4Ti3O 12 =6:1~12:1 is denoted as A:BTO=6:1~12:1; ii. Preparation of raw material - salt mixed powder: Weigh out CaCO3, SrCO3, BaCO3, La2O3 and Bi4Ti3O 12 Or weigh out CaCO3, SrCO3, BaCO3, PbO and Bi4Ti3O 12 As raw materials, they are placed together in a polytetrafluoroethylene ball mill jar, and a NaCl-KCl mixed salt is added, with the molar ratio of the raw materials to the NaCl-KCl mixed salt being 11:38~11:

118. The NaCl-KCl mixed salt is composed of NaCl and KCl in a molar ratio of 1:1; ZrO2 balls and anhydrous ethanol were added to the polytetrafluoroethylene ball milling jar; the polytetrafluoroethylene ball milling jar was placed in a ball mill and ball milled at a speed of 200~500 r / min for 12~48 h; the raw material-salt mixed powder required for the preparation of CSBLT was obtained; The amount of ZrO2 spheres added is 1.0 to 3.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials; the amount of anhydrous ethanol added is 1.0 to 3.0 times the sum of the mass of the NaCl-KCl mixed salt and the mass of the raw materials. iii. Calcination: The obtained raw material-salt mixed powder is poured into an alumina crucible and placed in a box-type resistance furnace; the box-type resistance furnace is heated to 900℃~1100℃ at a heating rate of 5~15℃ / min and maintained at this temperature for 2~8 hours; after the holding period, the temperature is cooled to 500~700℃ at a cooling rate of 5~15℃ / min; the furnace is then cooled to room temperature to complete the calcination. By calcination, (Ca) is obtained. 0.25 Sr 0.25 Ba 0.25 La 0.25 The product is a mixture of TiO3 and NaCl-KCl salt blocks and the byproduct Bi2O3, or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The product is a mixture of TiO3 with NaCl-KCl salt blocks and the byproduct Bi2O3; The NaCl-KCl salt block is a lumpy substance formed from the unevaporated NaCl-KCl mixed salt added to the raw materials before calcination; the byproduct Bi2O3 is the Bi2O3 produced from the precursor during the calcination process. 3+ and Bi2O2 2+ The granular material formed by the removal of the layer; iv. Water washing: During the water washing process, the obtained (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 A mixture of TiO3 and NaCl-KCl salt blocks and the byproduct Bi2O3, or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The mixture of TiO3, NaCl-KCl salt block and byproduct Bi2O3 was placed in a beaker, and deionized water was added to submerge the mixture. Cover with plastic wrap; place the beaker in an oven at 60-90°C and soak for 48 hours to dissolve the salt in the deionized water; pour off the supernatant; add deionized water again and submerge the mixture. The beaker was placed in a magnetic stirrer at a speed of 200-500 r / min, and the product was pulverized by magnetic stirring for 4-6 hours to obtain the pulverized mixed product. After the grinding process is complete, deionized water is repeatedly added to the resulting pulverized mixture to treat the (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 TiO3 and NaCl-KCl salt blocks and byproducts Bi2O3 or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The product of mixing TiO3 with NaCl-KCl salt blocks and the byproduct Bi2O3 was repeatedly washed and filtered until no Cl was detected in the supernatant using AgNO3 reagent. - After washing with water, the NaCl-KCl salt block was removed, yielding (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 A mixture of TiO3 and the byproduct Bi2O3; The pulverized mixture was repeatedly washed and filtered with deionized water until no Cl- was detected in the supernatant using AgNO3 reagent. - After washing with water, (Ca) salt block with NaCl-KCl removed is obtained. 0.25 Sr 0.25 Ba 0.25 Pb 0.25 A mixture of TiO3 and the byproduct Bi2O3; v. Pickling: The obtained (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 A mixture of TiO3 and the byproduct Bi2O3, or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The mixture of TiO3 and byproduct Bi2O3 was placed in a beaker and placed in a magnetic stirrer, and a 25% nitric acid solution was added. According to (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 The mass of TiO3 or (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The amount of nitric acid used is determined by the mass of TiO3. Specifically, 5g (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 TiO3 or 5g (Ca 0.25 Sr 0.25 Ba 0.25 Pb 0.25 TiO3 corresponds to 265 mL of nitric acid solution; Multiple additions of nitric acid solution (Ca) 0.25 Sr 0.25 Ba 0.25 La 0.25 The mixture of TiO3 and the byproduct Bi2O3, or the Ca2+ solution with added nitric acid. 0.25 Sr 0.25 Ba 0.25 Pb 0.25 The mixture of TiO3 and the byproduct Bi2O3 was magnetically stirred; each stirring and washing session lasted 20 minutes, and the total stirring time during acid washing was 2-6 hours; after stirring, deionized water was repeatedly added for washing until the supernatant in the beaker could not be detected by AgNO3 solution. - After acid washing, CSBPT powder or CSBLT powder with Bi2O3 byproduct removed is obtained. ⅵ Drying: The obtained CSBPT or CSBLT powder with Bi2O3 removed byproduct was dried in an oven at 60 °C for 24 h to obtain high-entropy lamellar perovskite structure powder material CSBPT or high-entropy lamellar perovskite structure powder material CSBLT.

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