A high-entropy rare-earth titanate ceramic coating material and its preparation method

Abstract

The present invention relates to a high-entropy rare earth titanate ceramic coating material and a preparation method thereof, belonging to the technical field of high-entropy ceramic materials. The phase composition of the coating material is (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO 3+δ . The preparation method is to wet ball-mill and mix the raw material powders evenly to form a slurry, dry it, then heat it up to 900 °C to 1000 °C and keep it at a constant temperature for pre-calcination for 2 h to 3 h, cool it with the furnace, then heat it up to 1300 °C to 1400 °C and keep it at a constant temperature for calcination for 10 h to 15 h, and then cool it down to obtain the coating material. The coating material is successfully prepared into an ideal new high-entropy rare earth titanate ceramic coating material by the design addition of doping elements and by adjusting process parameters, which changes its crystal structure, microstructure and oxygen vacancy defect concentration, making the density of the coating bulk material greater than 98.4%, the Vickers hardness 10 GPa to 12 GPa, and the thermal conductivity 1.39 W·m ‑1 ·k ‑1 ~1.75 W·m ‑1 ·k ‑1 ; The process flow for preparing the coating material by the high-temperature solid-phase reaction method is simple, the preparation cost is low, and it is easy to promote.

Description

Technical Field

[0001] The present invention relates to a high-entropy rare-earth titanate ceramic coating material and a preparation method thereof, and specifically, to a (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO 3+δ ceramic coating material and a preparation method thereof, belonging to the technical field of high-entropy ceramic materials. Background Art

[0002] In the face of extremely harsh environments, the thermal conductivity of materials needs to be as low as possible in order to minimize heat diffusion while maintaining normal operation. Thermal barrier coatings are one of the classic applications that urgently require low thermal conductivity, and are currently recognized as the most effective method to significantly increase the service temperature of superalloys. Yttria-stabilized zirconia (YSZ) is a widely used thermal barrier coating material, but when the temperature is higher than 1200 °C, YSZ will experience degradation of thermophysical and mechanical properties such as phase transformation, reduced strain tolerance, and high thermal conductivity, ultimately leading to the failure of the thermal barrier coating, deterioration of device performance and service life, and not meeting the requirements of the next-generation engines. Therefore, it is crucial to develop new ceramic materials with excellent heat insulation performance to expand the application scope of ceramic materials in the field of thermal protection.

[0003] In past research, the role of entropy has hardly been considered in material development. High entropy is a new material design concept first proposed by Yeh and first applied to the ceramic field by Rost in 2015. Rost reported high-entropy oxides. High-entropy ceramics have attracted increasing attention due to their high thermal stability, superior mechanical properties, and good corrosion resistance, including high-entropy oxides, high-entropy carbides, and high-entropy borides. But until 2021, the most papers published on high-entropy ceramics were still high-entropy oxides (HEOs) because of their specific properties and potential applications, such as in the fields of thermal protection, catalysis, electrical properties, etc. Perovskite-type oxides (ABO3) are composed of angularly shared BO3 octahedra, and A metal ions are located in the interstitial positions therein, which has attracted extensive attention. This structural feature enables ABO3 to have multiple choices in composition and configuration, with customized mechanical and thermal properties. Highly disordered high-entropy ceramics have a large lattice distortion rate and a huge crystal site mass fluctuation effect, which can effectively reduce the thermal conductivity of materials, which is a key characteristic in the application of thermal barrier coating (TBC) materials. Therefore, the multi-component strategy should be a suitable choice to further improve the thermal barrier performance of perovskite titanates. Researchers doped multiple rare-earth elements in equal proportions at the A-site or B-site of perovskite ABO3 to maximize the entropy effect.

[0004] Although there have been a large number of reports on high-entropy rare-earth titanate oxides, the high-entropy rare-earth titanate oxide material with the phase composition of (Ca 0.25 Sr 0.25 Ba 0.25 La 0.25 )TiO 3+δ reported by Zhang Ping et al. has a lattice thermal conductivity of 2.5 W·m -1 ·k -1 at 1073 K, and its thermal barrier performance needs to be improved. At the same time, the samples prepared by the high-temperature solid-state reaction method often have defects such as low density and low Vickers hardness.

[0005] In recent years, La 1-x Sr x TiO 3+δ layered perovskite ceramics have attracted a large amount of research due to their excellent near-infrared light reflection performance. However, in extreme environments, due to the lack of thermal stability, oxygen atoms will escape from the lattice, resulting in the rearrangement of its special layered structure, and then leading to a decrease in light reflectivity, a reduction in heat insulation ability, and poor thermal protection effect. At the same time, the samples prepared by the high-temperature solid-state reaction method often have defects such as low density and low Vickers hardness. Summary of the Invention

[0006] To overcome the defects of the prior art, the purpose of the present invention is to provide a high-entropy rare-earth titanate ceramic coating material and a preparation method thereof. By designing and adding doping elements and adjusting process parameters, an ideal new high-entropy rare-earth titanate ceramic coating material (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO 3+δ is successfully prepared, so that its crystal structure, microstructure and oxygen vacancy defect concentration are changed, and the density of the coating bulk material is greater than 98.4%, the Vickers hardness is 10 GPa - 12 GPa, and the thermal conductivity is 1.39 W·m -1 ·k -1 -1.75 W·m -1 ·k -1 at 25 °C - 1200 °C; The process flow for preparing the coating material by the high-temperature solid-state reaction method is simple, the preparation cost is low, and it is easy to promote.

[0007] To achieve the purpose of the present invention, the following technical solutions are provided.

[0008] A high-entropy rare-earth titanate ceramic coating material, the phase composition of the coating material is (La 0.3 K 0.1 Ca0.2 Sr 0.2 Ba 0.2 )TiO 3+δ 。

[0009] A preparation method of a high-entropy rare-earth titanate ceramic coating material according to the present invention, the method steps are as follows:

[0010] (1) According to the phase composition of the coating material, weigh each raw material powder in a stoichiometric ratio, and use wet ball milling to mix evenly to form a slurry;

[0011] In step (1):

[0012] The raw material powders are powders of lanthanum oxide, potassium carbonate, strontium oxide, barium oxide, calcium oxide and titanium dioxide.

[0013] Preferably, the particle sizes of the raw material powders are all 1 μm to 5 μm, and the purities are all ≥99.9%.

[0014] Preferably, the mass ratio of the grinding balls to the raw material powders in the ball milling is 2:1 to 4:1.

[0015] Preferably, the ball milling medium in the ball milling is anhydrous ethanol.

[0016] Preferably, the ball milling speed in the ball milling is 300 r / min to 400 r / min, and the ball milling time is 12 h to 24 h.

[0017] (2) Dry the slurry prepared in step (1) to obtain a powder, heat the powder to 900 °C to 1000 °C and keep it at a constant temperature for pre-calcination for 2 h to 3 h, then cool it with the furnace, and then heat it to 1300 °C to 1400 °C and keep it at a constant temperature for calcination for 10 h to 15 h, and then cool it down to prepare a high-entropy rare-earth titanate ceramic coating material according to the present invention.

[0018] In step (2):

[0019] Preferably, rotary evaporation is used for drying, specifically as follows:

[0020] Set the water bath heating temperature to 65 °C to 85 °C, perform rotary evaporation at a rotation speed of 20 r / min to 30 r / min, and then dry the powder after rotary evaporation at 100 °C.

[0021] Preferably, the slurry is dried, ground, and sieved to obtain the sieved powder, and then heated for pre-calcination.

[0022] Preferably, the heating rate of the pre-calcination is 5 °C / min to 10 °C / min.

[0023] Preferably, the heating rate of the calcination is 5 °C / min to 10 °C / min.

[0024] Preferably, during the cooling process, first cool down at a cooling rate of 5 °C / min to 10 °C / min to 900 °C to 1000 °C, and then cool down to room temperature with the furnace.

[0025] A high-entropy rare earth titanate ceramic coating is prepared on a stainless steel substrate using the high-entropy rare earth titanate ceramic coating material described in the present invention.

[0026] Beneficial effects

[0027] (1) The present invention provides a high-entropy rare earth titanate ceramic coating material. By designing and adding doping elements and adjusting process parameters, a novel A-site non-equimolar high-entropy perovskite coating material of (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO 3+δ is successfully prepared. The coating material is a single-phase compound with a perovskite crystal structure. The density of the coating bulk material is greater than 98.4%, the Vickers hardness is 10 GPa to 12 GPa, and the thermal conductivity is 1.39 W·m -1 ·k -1 ~1.75 W·m -1 ·k -1 at 25 °C to 1200 °C. The coating material has a low thermal conductivity, enriches the types of high-entropy ceramics, and has broad application prospects as a thermal protection type high-temperature thermal insulation material.

[0028] (2) The present invention provides a high-entropy rare earth titanate ceramic coating material. The types, contents and synergistic technical effects of various elements in the coating material change the crystal structure, microstructure and oxygen vacancy defect concentration of the coating material. By increasing the element ratio of La 3+ and correspondingly reducing K + , due to the increase in the average valence state of A-site elements, the formation of oxygen vacancies will be inhibited. And the formation energy of LaTiO3 is lower than that of KTiO3, and the increase in the bond strength between metal atoms and oxygen atoms can also inhibit oxygen vacancies; by inhibiting the oxygen vacancy content, the reflection performance of the coating material is improved, the heat insulation ability is enhanced, and the thermal barrier performance is improved.

[0029] (3) The present invention provides a preparation method of a high-entropy rare earth titanate ceramic coating material. The method is ball milling and high-temperature solid-phase reaction method. The preparation process flow is simple, the preparation cost is low, and it is easy to promote.

[0030] (4) The present invention provides a method for preparing a high-entropy rare earth titanate ceramic coating material. In the preparation method, in step (1), the raw material powders are fully and uniformly mixed by wet ball milling, so that the element distribution of the high-entropy rare earth titanate ceramic coating material synthesized at high temperature is uniform, and there will be no agglomeration and enrichment of a certain rare earth element.

[0031] (5) The present invention provides a method for preparing a high-entropy rare earth titanate ceramic coating material. In the preparation method, in step (2), the powder is heated to 900 °C to 1000 °C and isothermal pre-calcined for 2 h to 3 h, and then cooled with the furnace, and then heated to 1300 °C to 1400 °C and isothermal calcined for 10 h to 15 h and then cooled. Since the melting point of potassium carbonate in the raw materials is 891 °C and it is unstable at high temperature and will decompose when heated to produce carbon dioxide gas, the temperature and time of pre-calcination in the two-step calcination can make potassium carbonate fully decompose and discharge gas, which can improve the density of the coating bulk material to a certain extent. If the temperature is too low in the subsequent calcination, problems such as the prepared material not being a single perovskite structure will occur, and if the temperature is too high, problems such as the prepared material melting will occur; pre-calcination is an important condition for preparing the coating material. If the pre-calcination step is omitted, problems such as the presence of a second phase in the phase structure of the prepared material will occur;

[0032] Preferably, after the slurry is dried, it is ground and sieved to obtain the sieved powder, and then heated for pre-calcination, so that the calcined powder particles are uniform, which can make the particle size distribution of the coating material uniform and have a good particle morphology.

[0033] (6) The present invention provides a high-entropy rare earth titanate ceramic coating. The coating uses a high-entropy rare earth titanate ceramic coating material described in the present invention and is suitable for use in combination with a stainless steel substrate; the coating has a low thermal conductivity and has broad application prospects as a thermal protection type high-temperature heat insulation material. Description of the Drawings

[0034] Figure 1 It is an X-ray diffraction (XRD) pattern of the powder sample prepared in Example 1.

[0035] Figure 2 It is a scanning electron microscope (SEM) image of the bulk sample prepared in Example 2, and the result image of surface scanning element analysis of this image.

[0036] Figure 3 It is a thermal conductivity curve graph of the bulk sample prepared in Example 2. Detailed Embodiments

[0037] The present invention will be further described below in conjunction with the specific embodiments. Among them, the methods are all conventional methods unless otherwise specified, and the raw materials can all be obtained from public commercial channels unless otherwise specified.

[0038] In the following examples:

[0039] The particle sizes of the raw material powders are all 1 μm to 5 μm, and the purities are all ≥ 99.9%.

[0040] The following tests were carried out on the prepared powder samples and bulk samples:

[0041] (1) X-ray diffraction (XRD)

[0042] The test was carried out using an Empyrean model instrument from PANalytical B.V., the Netherlands.

[0043] (2) Field emission scanning electron microscope (SEM)

[0044] Observation was carried out using a Zeiss Sigma300 field emission scanning electron microscope.

[0045] (3) Apparent density

[0046] The apparent density was measured by fitting and calculating the porosity using ImageJ software in combination with the cross-sectional SEM morphology area of the sample at the same magnification.

[0047] (4) Vickers hardness (Hv)

[0048] The measurement was carried out according to the national standard GB / T 16534-2009 using a Vickers hardness tester. More than 10 valid values were randomly selected and measured under each load, and the arithmetic mean and standard deviation were the Vickers hardness value and error under the corresponding load.

[0049] (5) Thermal conductivity

[0050] The thermal conductivity of the bulk sample was measured using a German-NETZSCH-LFA427 laser thermal conductivity meter.

[0051] Example 1

[0052] (1) According to the phase composition of the coating material (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO 3+δ , each raw material powder was weighed according to the stoichiometric ratio:

[0053] The raw material powder is a powder of lanthanum oxide, potassium carbonate, strontium oxide, barium oxide, calcium oxide and titanium dioxide. Weigh the raw material powder according to the molar ratio of seven elements La, K, Ca, Sr, Ba, Ti and O in the raw material powder being 3:1:2:2:2:10:30 and add it into a ball milling tank. Add absolute ethanol into the ball milling tank as the ball milling medium, and add zirconia ball milling beads into the ball milling tank according to the ball-to-material ratio of 2:1 of the ball milling balls to the raw material powder. The used ball milling balls are composed of zirconia balls with diameters of 20 mm, 10 mm and 5 mm mixed according to the quantity ratio of 1:2:4; Ball mill at a speed of 300 r / min on a planetary ball mill for 12 h to obtain a uniformly mixed ball milling slurry.

[0054] (2) Transfer the ball milling slurry prepared in step (1) to a rotary evaporator, set the water bath heating temperature to 65 °C, perform rotary evaporation at a rotary speed of 20 r / min, then place the powder after rotary evaporation in an oven at 100 °C for drying, and then screen the dried powder through a 200-mesh sieve; Place the sieved powder in a muffle furnace and heat it at a heating rate of 10 °C / min to 900 °C for constant temperature pre-calcination for 2 h, and then cool it with the furnace; Then heat it at a heating rate of 10 °C / min to 1300 °C for constant temperature calcination for 10 h to prepare the final product powder, and then cool it at a cooling rate of 5 °C / min to 1000 °C, and then cool it with the furnace to room temperature. After taking it out, grind it with a mortar until there are no obvious particles, as the powder sample for testing.

[0055] In order to conduct tests on scanning electron microscope observation, density, Vickers hardness and thermal conductivity, it is necessary to make the powder sieved in step (2) of this example into a block sample for testing. The specific method is as follows:

[0056] First pre-press the pre-calcined powder into shape under a pressure of 8 MPa, and then press it into shape under a pressure of 180 MPa. After maintaining the pressure for 4 min, a pressed block is obtained; Place the pressed block in a muffle furnace, heat it at a heating rate of 10 °C / min to 1300 °C for constant temperature calcination for 10 h, then cool it at a cooling rate of 5 °C / min to 1000 °C, and then cool it with the furnace to room temperature as the block sample for testing.

[0057] The powder sample and block sample prepared in this example are tested as follows:

[0058] (1) X-ray diffraction (XRD)

[0059] The test results are as Figure 1 shown. It can be seen that the powder sample conforms to the diffraction peak positions of a typical perovskite crystal structure, and there are almost no impurity peaks.

[0060] (2) Field emission scanning electron microscope (SEM)

[0061] The microstructure and elemental distribution in the bulk sample were observed using a Zeiss Sigma 300 field emission scanning electron microscope. According to the characterization results, there are no obvious pores and cracks, and the five metal elements are evenly distributed in the high-entropy perovskite oxide without obvious elemental segregation.

[0062] In summary, it can be seen that the end product prepared in this example is a high-entropy rare earth titanate ceramic coating material (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO 3+δ , which is a single-phase compound with a perovskite crystal structure.

[0063] (3) Apparent density

[0064] Since the total weight of the bulk sample is small, the error in calculating the ratio of pore volume to material volume using Archimedes' law is relatively large. Therefore, ImageJ software was used to fit and calculate the porosity in combination with the cross-sectional SEM morphology area of the sample at the same magnification, and the apparent density of the bulk sample was obtained as 98.5%.

[0065] (4) Vickers hardness (Hv)

[0066] The Vickers hardness of the bulk sample was measured to be 10.8 GPa using an HX-1000TM / LCD hardness tester.

[0067] (5) Thermal conductivity

[0068] The thermal conductivity measured at 25 °C to 1200 °C was 1.39 W·m -1 ·k -1 ~1.68 W·m -1 ·k -1 .

[0069] Example 2

[0070] (1) Zirconia milling beads were added to the milling jar according to a ball-to-powder mass ratio of 4:1 for ball milling. The ball milling was carried out on a planetary ball mill at a speed of 400 r / min for 24 h; the rest was the same as step (1) of Example 1.

[0071] (2) Transfer the ball-milled slurry prepared in step (1) to a rotary evaporator, set the water bath heating temperature at 85 °C, perform rotary evaporation at a rotation speed of 30 r / min, then place the powder after rotary evaporation in an oven at 100 °C for drying, and then screen the dried powder through a 200-mesh sieve; place the sieved powder in a muffle furnace and heat it at a heating rate of 5 °C / min to 900 °C for constant-temperature pre-calcination for 3 h, and then cool it down with the furnace; then heat it at a heating rate of 5 °C / min to 1400 °C for constant-temperature calcination for 10 h to prepare the final product powder, then cool it down to 900 °C at a cooling rate of 10 °C / min, and then cool it down to room temperature with the furnace, take it out and grind it with a mortar until there are no obvious particles, which is used as the powder sample for testing.

[0072] In order to conduct tests on scanning electron microscopy observation, density, Vickers hardness and thermal conductivity, the powder sieved in step (2) of this example needs to be made into a bulk sample for testing, and the specific method is as follows:

[0073] First, pre-press the pre-calcined powder into a shape under a pressure of 9 MPa, and then press it into a shape under a pressure of 200 MPa. After holding the pressure for 5 min, a pressed bulk is obtained; place the pressed bulk in a muffle furnace, heat it at a heating rate of 5 °C / min to 1400 °C for constant-temperature calcination for 10 h, then cool it down to 900 °C at a cooling rate of 10 °C / min, and then cool it down to room temperature with the furnace, which is used as the bulk sample for testing.

[0074] The powder sample and bulk sample prepared in this example are tested as follows:

[0075] (1) X-ray diffraction (XRD)

[0076] According to the test results, it can be seen that the prepared product conforms to the diffraction peak positions of the typical perovskite crystal structure, and there are almost no impurity peaks.

[0077] (2) Field emission scanning electron microscopy (SEM)

[0078] Use a Zeiss Sigma300 field emission scanning electron microscope to observe the microstructure and element distribution in the bulk sample, and the characterization results are as Figure 2 shown. There are no obvious pores and cracks in the sample, and the five metal elements are evenly distributed in the high-entropy perovskite oxide, and there is no obvious element segregation.

[0079] To sum up, it can be known that the final product prepared in this example is a high-entropy rare earth titanate ceramic coating material (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO3+δ is a single-phase compound with a perovskite crystal structure.

[0080] (3) Relative density

[0081] Due to the relatively small total weight of the bulk sample, the error in calculating the ratio of the pore volume to the material volume using Archimedes' law is relatively large. Therefore, the ImageJ software was used to fit and calculate the porosity of the bulk sample in combination with the cross-sectional SEM morphology area of the sample at the same magnification, and the relative density of the bulk sample was obtained as 99.1%.

[0082] (4) Vickers hardness (Hv)

[0083] The Vickers hardness of the bulk sample was measured to be 12 GPa using an HX-1000TM / LCD hardness tester.

[0084] (5) Thermal conductivity

[0085] The test results are as Figure 3 shown. The thermal conductivity from 25 °C to 1200 °C was measured to be 1.39 W·m -1 ·k -1 ~1.75 W·m -1 ·k -1 .

Claims

1. A high-entropy rare earth titanate ceramic coating material, characterized in that: The phase composition of the coating material is (La 0.3 K 0.1 Ca 0.2 Sr 0.2 Ba 0.2 )TiO 3+δ .

2. A method for preparing a high-entropy rare earth titanate ceramic coating material as described in claim 1, characterized in that: The method steps are as follows: (1) According to the phase composition of the coating material, weigh each raw material powder in stoichiometric ratio, and use wet ball milling to mix evenly to form a slurry; the raw material powders are powders of lanthanum oxide, potassium carbonate, strontium oxide, barium oxide, calcium oxide, and titanium dioxide; (2) Dry the slurry to obtain a powder, heat the powder to 900 °C - 1000 °C and keep it at a constant temperature for pre-calcination for 2 h - 3 h, then cool it with the furnace, and then heat it to 1300 °C - 1400 °C and keep it at a constant temperature for calcination for 10 h - 15 h, and then cool it down to prepare a high-entropy rare earth titanate ceramic coating material.

3. The preparation method of a high-entropy rare earth titanate ceramic coating material according to claim 2, characterized in that: In step (1), the particle sizes of the raw material powders are all 1 μm - 5 μm, and the purities are all ≥99.9%.

4. The preparation method of a high-entropy rare earth titanate ceramic coating material according to claim 2 or 3, characterized in that: In step (1), the mass ratio of the grinding balls to the raw material powders for ball milling is 2:1 - 4:1; the ball milling medium for ball milling is anhydrous ethanol; the ball milling speed for ball milling is 300 r / min - 400 r / min, and the ball milling time is 12 h - 24 h.

5. The preparation method of a high-entropy rare earth titanate ceramic coating material according to claim 2, characterized in that: In step (2), the drying method is specifically: set the water bath heating temperature to 65 °C - 85 °C, perform rotary evaporation at a rotation speed of 20 r / min - 30 r / min, and then dry the powder after rotary evaporation at 100 °C.

6. The preparation method of a high-entropy rare-earth titanate ceramic coating material according to claim 2, characterized in that: In step (2), after the slurry is dried, it is ground and sieved to obtain the sieved powder, and then heated for pre-calcination.

7. The preparation method of a high-entropy rare earth titanate ceramic coating material according to claim 2, characterized in that: In step (2), the heating rate for pre-calcination is 5 °C / min - 10 °C / min; the heating rate for calcination is 5 °C / min - 10 °C / min; during the cooling process, first cool it at a cooling rate of 5 °C / min - 10 °C / min to 900 °C - 1000 °C, and then cool it with the furnace to room temperature.

8. The preparation method of a high-entropy rare earth titanate ceramic coating material according to claim 2, characterized in that: In step (2), rotary evaporation is used for drying, specifically: set the water bath heating temperature to 65 °C - 85 °C, perform rotary evaporation at a rotation speed of 20 r / min - 30 r / min, and then dry the powder after rotary evaporation at 100 °C; After the slurry is dried, it is ground and sieved to obtain the sieved powder, and then heated for pre-calcination; The heating rate for pre-calcination is 5 °C / min - 10 °C / min; the heating rate for calcination is 5 °C / min - 10 °C / min; during the cooling process, first cool it at a cooling rate of 5 °C / min - 10 °C / min to 900 °C - 1000 °C, and then cool it with the furnace to room temperature.

9. The preparation method of a high-entropy rare-earth titanate ceramic coating material according to claim 2, wherein: In step (1), the particle sizes of the raw material powders are all 1 μm - 5 μm, and the purities are all ≥99.9%; The mass ratio of the grinding balls to the raw material powders for ball milling is 2:1 - 4:1; the ball milling medium for ball milling is anhydrous ethanol; the ball milling speed for ball milling is 300 r / min - 400 r / min, and the ball milling time is 12 h - 24 h; In step (2), the drying method is specifically: set the water bath heating temperature to 65 °C - 85 °C, perform rotary evaporation at a rotation speed of 20 r / min - 30 r / min, and then dry the powder after rotary evaporation at 100 °C; After the slurry is dried, it is ground and sieved to obtain the sieved powder, and then heated for pre-calcination; The heating rate of pre-calcination is 5 °C / min to 10 °C / min; the heating rate of calcination is 5 °C / min to 10 °C / min; during the cooling process, first cool down at a cooling rate of 5 °C / min to 10 °C / min to 900 °C to 1000 °C, and then cool with the furnace to room temperature.

10. A high-entropy rare earth titanate ceramic coating, characterized in that: The coating is prepared on a high-temperature nickel-based alloy substrate by using a high-entropy rare-earth titanate ceramic coating material as described in claim 1.

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