Rare earth zirconate-based complex-phase high-entropy ceramic as well as preparation method and application thereof

Abstract

The invention provides rare earth zirconate-based complex-phase high-entropy ceramic as well as a preparation method and application thereof, and belongs to the technical field of ceramic materials. The rare earth zirconate-based complex-phase high-entropy ceramic disclosed by the invention comprises a rare earth zirconate high-entropy matrix (La < 0.2 > Gd < 0.2 > Y < 0.2 > Y 0.2 < Er < 0.2 >) 2 (Zr < 0.5 > Ti < 0.5 >) 2O7 with a pyrochlore structure and a second-phase rare earth manganate high-entropy material (La < 0.2 > Gd < 0.2 > Y < 0.2 > Y 0.2 < Er < 0.2 >) MnO3 with a perovskite structure. The rare earth zirconate-based complex-phase (pyrochlore-perovskite) high-entropy ceramic for shielding thermal radiation is prepared by taking high-entropy rare earth zirconate with a pyrochlore structure as a matrix and taking a rare earth manganate high-entropy material with a perovskite structure as a second phase (dopant). The prepared complex-phase high-entropy ceramic can effectively improve the thermal radiation shielding performance and hinder the radiation heat conduction at high temperature, thereby inhibiting the rapid increase of the thermal conductivity at high temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of ceramic materials, and in particular to a rare earth zirconate-based multiphase high-entropy ceramic and a preparation method and application thereof. Background Art

[0002] A thermal barrier coating refers to a multifunctional ceramic protective layer deposited on the surface of hot-end metal components of aeroengines and gas turbines, which plays the roles of heat insulation and protection between the hot gas flow and the engine components. It can significantly increase the operating temperature of the engine and multiply extend the service life of the engine. One of the most important functions of the thermal barrier coating is heat insulation, so low thermal conductivity is the key goal pursued by the ceramic materials for thermal barrier coatings.

[0003] At present, the research work on reducing the thermal conductivity of ceramic materials for thermal barrier coatings mainly focuses on hindering lattice heat conduction. Domestic and foreign scholars mainly develop new ceramic materials with low thermal conductivity from the following aspects. First, rare earth oxides are used to dope and modify traditional ZrO2 ceramic materials, and the thermal conductivity of the materials is reduced by increasing the number of defects (oxygen holes or oxygen vacancies) in the ceramics and the differences in doped ions. Second, rare earth composite ceramic materials with pyrochlore and fluorite structures (such as rare earth zirconates Re2Zr2O7, Re = La, Sm, Nd, Gd, etc.) are developed. The crystal structure of this type of material is more complex than that of ZrO2 ceramic materials and has lower thermal conductivity. Third, traditional ZrO2 ceramics or rare earth zirconate ceramic materials are high-entropied by multi-component doping. High-entropy ceramics are composed of five or more elements in equimolar or near-equimolar amounts, and their mixed configurational entropy is greater than 1.5R (ΔS mix = RlnN, where R is the molar gas constant and N is the number of equimolar elements). The high-entropy of ceramic materials will lead to severe lattice distortion, strengthen phonon scattering, resulting in a decrease in the phonon mean free path, thereby achieving the purpose of reducing the thermal conductivity.

[0004] However, for some thermal barrier coating ceramic materials that are infrared semi-transparent or completely transparent (high transmittance), as the temperature increases, the thermal radiation effect will intensify, and radiative heat conduction becomes more and more significant. The increase in radiative thermal conductivity at high temperatures will lead to a sharp increase in the thermal conductivity of the ceramic materials. Especially for some rare earth zirconates (including high-entropy rare earth zirconates) with low absorption coefficients, the contribution of radiative heat conduction will increase significantly above several hundred degrees Celsius. The increase in the thermal conductivity of thermal barrier coating ceramic materials at high temperatures will seriously affect their heat insulation effect and shorten the service life of the ceramic coating. The sharp increase in thermal conductivity at high temperatures caused by the thermal radiation effect is a common technical problem in the design and application of high-temperature thermal barrier coating materials and has become one of the main bottlenecks restricting their service temperature.

[0005] Therefore, fundamentally suppressing the increase in high-temperature radiative thermal conductivity is the key to developing new thermal barrier coating materials with low thermal conductivity. Summary of the Invention

[0006] The object of the present invention is to provide a rare earth zirconate-based multiphase high-entropy ceramic and its preparation method and application. The rare earth zirconate-based multiphase high-entropy ceramic can effectively improve the thermal radiation shielding performance, hinder the radiative heat conduction at high temperatures, and thus suppress the sharp increase in thermal conductivity at high temperatures.

[0007] In order to achieve the above object of the invention, the present invention provides the following technical solutions:

[0008] The present invention provides a preparation method of a rare earth zirconate-based multiphase high-entropy ceramic, comprising the following steps:

[0009] According to the chemical composition of the high-entropy perovskite structure as (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, mix MnO2, La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3 with water, and perform the first sanding treatment to obtain the first slurry; perform the first calcination on the first slurry to obtain the high-entropy perovskite structure powder;

[0010] According to the stoichiometric ratio of the rare earth zirconate high-entropy matrix as (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7, mix La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3, ZrO2, TiO2 with water, and perform the second sanding treatment to obtain the second slurry; perform the second calcination on the second slurry to obtain the rare earth zirconate high-entropy matrix;

[0011] Mix the high-entropy perovskite structure powder with the rare earth zirconate high-entropy matrix and water, perform the third sanding treatment to obtain the third slurry; perform the third calcination on the third slurry to obtain the rare earth zirconate-based multiphase high-entropy ceramic.

[0012] Preferably, in the first slurry, the molar ratio of La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3 is 1:1:1:1:1.

[0013] Preferably, the molar ratio of the high-entropy perovskite structure powder to the rare earth zirconate high-entropy matrix is 2x:(1-x), where x = 0.05 - 0.2.

[0014] Preferably, the rotation speeds of the first, second, and third grinding treatments are independently 2300-2700 r / min, and the times are independently 4-6 h.

[0015] Preferably, the solid contents of the first, second, and third slurries are independently 45-55 wt%.

[0016] Preferably, the temperature of the first calcination is 1200-1400 °C, and the time of the first calcination is 3-5 h.

[0017] Preferably, the temperature of the second calcination is 1400-1500 °C, and the time of the second calcination is 5-8 h.

[0018] Preferably, the temperature of the third calcination is 1450-1500 °C, and the time of the third calcination is 8-10 h.

[0019] The present invention provides a rare earth zirconate-based composite high-entropy ceramic prepared by the preparation method described in the above technical solution.

[0020] The present invention provides the application of the rare earth zirconate-based composite high-entropy ceramic described in the above technical solution in the field of thermal barrier coatings.

[0021] The present invention provides a preparation method of a rare earth zirconate-based composite high-entropy ceramic. This rare earth zirconate-based composite high-entropy ceramic includes a pyrochlore-structured rare earth zirconate high-entropy matrix (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 and a perovskite-structured second-phase rare earth manganate high-entropy material (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3. The present invention uses the pyrochlore-structured (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 high-entropy rare earth zirconate as the matrix, and uses the perovskite-structured rare earth manganate high-entropy material as the second phase (dopant) to prepare a rare earth zirconate-based composite (pyrochlore-perovskite) high-entropy ceramic for shielding thermal radiation.

[0022] Due to the rapid increase in the thermal conductivity of the high-entropy rare-earth zirconate matrix at 600 °C, and at high temperatures, photon heat conduction usually dominates. Secondly, the photon thermal conductivity is related to the absorption coefficient and scattering coefficient of the material. When infrared radiation is incident on the material surface, absorption, reflection, and transmission will occur. According to the law of conservation of energy, the sum of the three is 1. The ABO3 material has a high infrared emissivity and can effectively shield infrared radiation. In the present invention, the high-entropy perovskite structure with a high absorption coefficient is incorporated into the rare-earth zirconate matrix as the second phase, which can effectively shield thermal radiation and better protect the matrix metal. Therefore, the composite high-entropy ceramic prepared in the present invention can effectively improve the thermal radiation shielding performance, hinder the radiative heat conduction at high temperatures, and thus inhibit the sharp increase in thermal conductivity at high temperatures. Description of the Drawings

[0023] Figure 1 XRD pattern of (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 in Example 1;

[0024] Figure 2 XRD patterns of (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 ceramic in Comparative Example 1 and four kinds of rare-earth zirconate-based high-entropy ceramics (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7-(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 in Example 1;

[0025] Figure 3 XRD pattern of perovskite structure powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 in Example 1;

[0026] Figure 4For the four kinds of rare earth zirconate-based high-entropy ceramics ((1-x)mol(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 / 2xmol(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 (0.05; 0.1; 0.15; 0.2) and the XRD patterns of the (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 ceramic (REZT) in Comparative Example 1. Specific Embodiments

[0027] In the present invention, unless otherwise specified, the raw materials or reagents required for preparation are all commercially available products well-known to those skilled in the art.

[0028] The present invention provides a method for preparing a rare earth zirconate-based composite high-entropy ceramic, comprising the following steps:

[0029] According to the chemical composition of the high-entropy perovskite structure as (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, mix MnO2, La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3 with water, and perform the first sanding treatment to obtain the first slurry; perform the first calcination on the first slurry to obtain the high-entropy perovskite structure powder;

[0030] According to the stoichiometric ratio of the rare earth zirconate high-entropy matrix as (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7, mix La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3, ZrO2, TiO2 with water, and perform the second sanding treatment to obtain the second slurry; perform the second calcination on the second slurry to obtain the rare earth zirconate high-entropy matrix;

[0031] Mix the high-entropy perovskite-structured powder with the rare-earth zirconate high-entropy matrix and water, and perform a third sanding treatment to obtain a third slurry; subject the third slurry to a third calcination to obtain a rare-earth zirconate-based composite high-entropy ceramic.

[0032] In the present invention, in the first slurry, the molar ratio of La2O3, Gd2O3, Y2O3, Yb2O3, and Er2O3 is preferably 1:1:1:1:1; the chemical composition of the high-entropy perovskite-structured powder is (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3. This high-entropy perovskite-structured powder serves as the second-phase rare-earth manganate high-entropy material.

[0033] In the present invention, the molar ratio of the high-entropy perovskite-structured powder to the rare-earth zirconate high-entropy matrix is preferably 2x:(1 - x), where x = 0.05 to 0.2, and more preferably 0.1 to 0.15.

[0034] In the present invention, the rotational speeds of the first sanding treatment, the second sanding treatment, and the third sanding treatment are independently preferably 2300 - 2700 r / min, further preferably 2500 - 2700 r / min, and more preferably 2600 - 2700 r / min; the times are independently preferably 4 - 6 h, further preferably 4.5 - 5.5 h, and more preferably 5 h.

[0035] In the present invention, the solid contents of the first slurry, the second slurry, and the third slurry are independently preferably 45 - 55 wt%, further preferably 46 - 53 wt%, and more preferably 49 - 50 wt%.

[0036] In the present invention, before the first calcination, it further includes: first drying the first slurry, where the temperature of the first drying is 100°C and the time is 24 h.

[0037] In the present invention, the temperature of the first calcination is preferably 1200 - 1400°C, further preferably 1200 - 1300°C, and more preferably 1300 - 1350°C; the time of the first calcination is preferably 3 - 5 h, further preferably 3.5 - 4.5 h, and more preferably 4 h.

[0038] In the present invention, before the second calcination, it further includes: second drying the second slurry, where the temperature of the second drying is 100°C and the time is 24 h.

[0039] In the present invention, the temperature of the second calcination is preferably 1400 - 1500 °C, more preferably 1425 - 1480 °C, and still more preferably 1450 - 1480 °C; the time of the second calcination is preferably 5 - 8 h, more preferably 5.5 - 7.5 h, and still more preferably 6 - 7 h.

[0040] In the present invention, before the third calcination, it further includes: drying the third slurry for the third time, then dry-pressing the powder obtained after drying to form a ceramic green body, and subjecting the ceramic green body to the third calcination; the dry pressing is preferably pre-pressing at 20 MPa for 1 min first, and then cold isostatic pressing at 200 MPa for 90 s; the temperature of the third drying is 100 °C and the time is 24 h.

[0041] In the present invention, the temperature of the third calcination is preferably 1450 - 1500 °C, and the time of the third calcination is preferably 8 - 10 h, more preferably 8 - 9.5 h, and still more preferably 8.5 - 9 h.

[0042] The present invention provides a rare earth zirconate-based composite high-entropy ceramic prepared by the preparation method described in the above technical solution.

[0043] The present invention provides the application of the rare earth zirconate-based composite high-entropy ceramic described in the above technical solution in the field of thermal barrier coatings. The present invention has no special limitation on the method of the application, and it can be applied according to the methods well-known in the art.

[0044] The specific embodiments of the present invention will be described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention. The experimental methods described in the embodiments of the present invention are all conventional methods unless otherwise specified.

[0045] The following experimental methods and detection methods are all conventional methods unless otherwise specified; the following reagents and raw materials are all commercially available unless otherwise specified.

[0046] Example 1

[0047] Taking the total mass of the raw materials MnO2, La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3 as 1000 g, accurately weigh 318.28 g, 131.37 g, 146.16 g, 91.05 g, 158.91 g, 154.23 g of MnO2, La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3 respectively. Add deionized water and adjust the solid content of the slurry to 45 wt%. Pour the slurry into a sand mill and grind it at ball milling speeds of 2500 r / min and 2700 r / min for 2 h respectively. Dry the milled slurry at 100 °C for 24 h, and then calcine the obtained powder at 1400 °C for 5 h to obtain a perovskite structure powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, denoted as REM;

[0048] Calculated based on the total mass of the raw materials La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3, ZrO2, TiO2 being 1000 g, accurately weigh 120.40 g, 133.95 g, 83.44 g, 145.63 g, 141.35 g, 227.70 g, 147.56 g of La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3, ZrO2, TiO2 respectively according to the stoichiometric ratio of (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7. Add deionized water and adjust the solid content of the slurry to 45 wt%. Pour the slurry into a sand mill and grind it at ball milling speeds of 2500 r / min and 2700 r / min for 2 h respectively. Dry the milled slurry at 100 °C for 24 h, and then calcine the obtained powder at 1500 °C for 6 h to obtain a (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder;

[0049] Taking the raw materials (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 and (La 0.2 Gd 0.2 Y0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder total mass is calculated as 1000 g. According to (1 - x)(mol)(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 / 2x(mol)(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 where (x = 0.05, 0.1, 0.15, 0.2) in turn. Accurately weigh the raw materials (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 are 46.02 g, 92.42 g, 139.22 g, 186.41 g in turn, (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powders are 953.98 g, 907.58 g, 860.78 g, 813.59 g in turn. Add deionized water respectively, adjust the solid content of the slurry to 45 wt%, pour the slurry into a sand mill, and sand mill at a ball milling speed of 2700 r / min for 4 h; dry the sand milled slurry at 100 °C for 24 h, then dry the obtained powder by dry pressing. First pre-press at 20 MPa for 1 min, and then cold isostatic press at 200 MPa for 90 s to obtain a ceramic green body. Finally, bake the ceramic green body at 1500 °C for 8 h to obtain four kinds of rare earth zirconate-based high-entropy ceramics (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7-(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3.

[0050] Comparative Example 1

[0051] The (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder obtained in Example 1 was dry-pressed into a green ceramic body, and the green ceramic body was calcined at 1500 °C for 8 h to obtain (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 ceramic, denoted as REZT.

[0052] Characterization and testing

[0053] The XRD pattern of the (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder obtained in Example 1 is as shown in Figure 1 . It can be seen from Figure 1 that the phase structure of the synthesized (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder is a single pyrochlore structure without the presence of other impurity phases.

[0054] Using the methods described in ASTM E1461 and ISO 22007-4, the (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 ceramic (REZT) obtained in Comparative Example 1 and the four kinds of (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7-(La 0.2 Gd 0.2 Y 0.2 Yb0.2 Er 0.2 )MnO3 was subjected to thermal conductivity testing, and the test results are as Figure 2 shown. From Figure 2 it can be seen that the thermal conductivity of (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 ceramics begins to increase sharply above 600 °C; however, after doping with (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, the increase in thermal conductivity above 600 °C is effectively inhibited, indicating that doping with (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 in rare-earth zirconate-based high-entropy ceramics (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7-(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 can effectively shield thermal radiation.

[0055] Since the increase in thermal conductivity at high temperatures is mainly dominated by photon thermal radiation. The thermal conductivity of REZT rises rapidly at high temperatures because REZT becomes infrared semi-transparent at high temperatures, and light directly acts on the substrate metal through REZT, resulting in too high a substrate temperature and thus affecting its use. When the second phase REM is incorporated, it can be clearly seen from the thermal conductivity Figure 2 that as the doping amount of the second phase increases, the thermal conductivity of the multiphase ceramic at high temperatures decreases significantly. Therefore, it shows that the incorporation of the second phase increases the absorption coefficient of the multiphase ceramic, most of the light is absorbed, and less light passes through the multiphase ceramic to the substrate metal. Therefore, it can effectively reduce the photon thermal conductivity and improve the thermal shielding performance.

[0056] The perovskite-structured powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2)The XRD pattern of MnO3 is as shown in Figure 3 . It can be seen from Figure 3 that the perovskite-structured powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 has a hexagonal perovskite structure and no other impurity phases exist.

[0057] Example 2

[0058] Mix the perovskite-structured powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 and (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 according to the following ratio (1 - x) mol (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 / 2x mol (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 where (x = 0.05, 0.1, 0.15, 0.2):

[0059] Calculated based on the total powder mass of 1000 g when x = 0.05, accurately weigh 46.02 g of the perovskite-structured powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, and the synthesized (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5) The mass of the 2O7 powder is 953.98 g. Deionized water is added, and the solid content of the slurry is adjusted to 45 wt%. The slurry is poured into a sand mill and milled at ball milling speeds of 2500 r / min and 2700 r / min for 2 h respectively. The milled slurry is dried at 100 °C for 24 h, and then the dried powder is dry-pressed. First, it is pre-pressed at 20 MPa for 1 min, and then cold isostatically pressed at 200 MPa for 90 s to obtain a ceramic green body.

[0060] Calculated according to the total powder mass of 1000 g with x = 0.1, accurately weigh the perovskite-structured powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 to be 92.42 g, and the synthesized (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder is 907.58 g. Deionized water is added, and the solid content of the slurry is adjusted to 45 wt%. The slurry is poured into a sand mill and milled at ball milling speeds of 2500 r / min and 2700 r / min for 2 h respectively. The milled slurry is dried at 100 °C for 24 h, and then the dried powder is dry-pressed. First, it is pre-pressed at 20 MPa for 1 min, and then cold isostatically pressed at 200 MPa for 90 s to obtain a ceramic green body;

[0061] Calculated according to the total powder mass of 1000 g with x = 0.15, accurately weigh the perovskite-structured powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 to be 139.22 g, and the synthesized (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder is 860.78 g. Deionized water is added, and the solid content of the slurry is adjusted to 45 wt%. The slurry is poured into a sand mill and milled at ball milling speeds of 2500 r / min and 2700 r / min for 2 h respectively. The milled slurry is dried at 100 °C for 24 h, and then the dried powder is dry-pressed. First, it is pre-pressed at 20 MPa for 1 min, and then cold isostatically pressed at 200 MPa for 90 s to obtain a ceramic green body;

[0062] Calculated based on a total powder mass of 1000 g with x = 0.2, accurately weigh 186.41 g of perovskite-structured powder (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, and 813.59 g of the synthesized (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 powder. Add deionized water to adjust the solid content of the slurry to 45 wt%. Pour the slurry into a sand mill and mill it at ball milling speeds of 2500 r / min and 2700 r / min for 2 h respectively. Dry the milled slurry at 100 °C for 24 h, and then dry-press the obtained powder. First, pre-press it at 20 MPa for 1 min, and then perform cold isostatic pressing at 200 MPa for 90 s to obtain a ceramic green body;

[0063] After calcining the above four ceramic green bodies (x = 0.05, 0.1, 0.15, 0.2) at 1500 °C for 8 h, four kinds of rare earth zirconate-based high-entropy ceramics (1 - x)mol(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 / 2xmol(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 are obtained, where (x = 0.05, 0.1, 0.15, 0.2).

[0064] The four kinds of rare earth zirconate-based high-entropy ceramics (1 - x)mol(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 E r 0.2 )2(Zr 0.5 Ti 0.5 )2O7 / 2xmol(La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3 (x = 0.05, 0.1, 0.15, 0.2) prepared in Example 2 and (La 0.2 Gd0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7 ceramics (REZT) is shown in the XRD pattern as Figure 4 follows. It can be seen from Figure 4 the comparison that the main crystal phase of the four rare earth zirconate-based high-entropy ceramics is the pyrochlore structure of high-entropy rare earth zirconate, and the second phase is LaMnO3 by comparing with the PDF standard card. Moreover, with the increase of the doping amount of (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, the perovskite structure in XRD becomes more and more obvious.

[0065] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A preparation method of a rare earth zirconate-based composite high-entropy ceramic, characterized in that, Including the following steps: According to the chemical composition of the high-entropy perovskite structure being (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )MnO3, mix MnO2, La2O3, Gd2O3, Y2O3, Yb2O3, and Er2O3 with water and perform a first sanding treatment to obtain a first slurry; perform a first calcination on the first slurry to obtain a high-entropy perovskite structure powder; According to the stoichiometric ratio of the rare earth zirconate high-entropy matrix of (La 0.2 Gd 0.2 Y 0.2 Yb 0.2 Er 0.2 )2(Zr 0.5 Ti 0.5 )2O7, mix La2O3, Gd2O3, Y2O3, Yb2O3, Er2O3, ZrO2, TiO2 with water and perform a second sanding treatment to obtain a second slurry; perform a second calcination on the second slurry to obtain a rare earth zirconate high-entropy matrix; Mix the high-entropy perovskite-structured powder with the rare-earth zirconate high-entropy matrix and water, and perform a third sanding treatment to obtain a third slurry; subject the third slurry to a third calcination to obtain a rare-earth zirconate-based composite high-entropy ceramic.

2. The preparation method according to claim 1, characterized in that, In the first slurry, the molar ratio of La2O3, Gd2O3, Y2O3, Yb2O3, and Er2O3 is 1:1:1:1:

1.

3. The preparation method according to claim 2, wherein The molar ratio of the high-entropy perovskite-structured powder to the rare-earth zirconate high-entropy matrix is 2x:(1 - x), where x = 0.05 to 0.

2.

4. The preparation method according to claim 3, characterized in that, The rotation speeds of the first sanding treatment, the second sanding treatment, and the third sanding treatment are independently 2300 to 2700 r / min, and the times are independently 4 to 6 h.

5. The preparation method according to claim 1 or 4, characterized in that, The solid contents of the first slurry, the second slurry, and the third slurry are independently 45 to 55 wt%.

6. The preparation method according to claim 1, characterized in that, The temperature of the first calcination is 1200 to 1400 °C, and the time of the first calcination is 3 to 5 h.

7. The preparation method according to claim 1, characterized in that, The temperature of the second calcination is 1400 to 1500 °C, and the time of the second calcination is 5 to 8 h.

8. The preparation method according to claim 1, wherein, The temperature of the third calcination is 1450 to 1500 °C, and the time of the third calcination is 8 to 10 h.

9. A rare-earth zirconate-based composite high-entropy ceramic prepared by the preparation method according to any one of claims 1 to 8.

10. Application of the rare-earth zirconate-based composite high-entropy ceramic according to claim 9 in the field of thermal barrier coatings.

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