A high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion and its preparation method

Abstract

The present invention discloses a high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance and a preparation method thereof, and relates to the technical field of thermal barrier coatings; the high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance has a chemical formula of (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4; wherein 0≤x≤1, 0≤y≤1, and x+y=1, and the density is ≥95%. The present invention also provides methods for preparing and using the aforementioned high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance. The high-entropy ceramic material of the present invention exhibits excellent fracture toughness and CMAS corrosion resistance, effectively resolving the problems of existing thermal barrier coating materials, such as unsatisfactory fracture toughness and weak CMAS corrosion resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal barrier coatings, and in particular to a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion and a preparation method thereof. Background Art

[0002] Thermal barrier coatings (TBCs) technology is a key technology for improving the temperature-bearing capacity of aircraft engines. However, with the continuous increase in aircraft engine operating temperatures, molten ambient deposit (CMAS) corrosion has gradually become the main form of TBC failure. Traditional TBC materials, such as yttria-stabilized zirconia (YSZ), have defects such as premature coating failure and insufficient temperature bearing capacity. They can no longer meet the requirements of aircraft engines for resisting high-temperature oxidation, thermal shock, and external corrosion. Therefore, there is an urgent need to develop new TBC materials with excellent comprehensive properties such as low thermal conductivity, high hardness, high toughness, and high-temperature corrosion resistance.

[0003] Rare earth tantalates or rare earth niobates (RETa / NbO4) are a new potential thermal barrier coating material. However, niobates undergo a phase transition at around 800°C, while tantalates undergo a phase transition at around 1300-1400°C, resulting in structural instability. Previous studies of high-entropy rare earth niobates have also demonstrated poor high-temperature phase stability, undergoing a phase transition at around 850°C, and exhibited poor resistance to CMAS corrosion. Therefore, the present invention incorporates tantalum into rare earth niobates to improve their phase stability, mechanical properties, and CMAS corrosion resistance. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance and a preparation method thereof. The high-entropy ceramic material has excellent high fracture toughness and CMAS corrosion resistance, which effectively solves the problems of unsatisfactory fracture toughness and weak CMAS corrosion resistance of thermal barrier coating materials in the prior art.

[0005] The technical solution of the present invention to solve the above technical problems is as follows: a high entropy ceramic material with high fracture toughness and resistance to CMAS corrosion is provided, whose chemical formula is (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4; where 0≤x≤1, 0≤y≤1, and x+y=1, and the density is ≥95%.

[0006] Further, y=0.5, 0.8.

[0007] The present invention also provides a method for preparing the high-entropy ceramic material having high fracture toughness and resistance to CMAS corrosion, comprising the following steps:

[0008] S1. Mixing the pretreated oxide powder and dispersant, and ball milling to obtain slurry A; the oxide powder includes Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder and Ta2O5 powder;

[0009] S2, drying, grinding and sieving the slurry A in sequence, then sintering it in an SPS sintering mold, and cooling it to room temperature to obtain a ceramic block;

[0010] S3. Annealing the ceramic block at 1300-1600 °C for 2-5 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0011] Furthermore, in step S1, during pretreatment, the oxide powder is calcined at 800-1000° C. for 2-3 h.

[0012] Furthermore, in step S1, the oxide powder has a particle size of 1-3 μm and a purity of ≥99.99%.

[0013] Furthermore, in step S1, the dispersant is anhydrous ethanol; and the mass ratio of the oxide powder to the dispersant is 1:0.5-0.6.

[0014] Further, in step S1, ball milling is performed at 300-400 rpm for 12-48 h.

[0015] Furthermore, in step S2, the product is dried at 70-90° C. for 12-24 h, ground for 5-7 min, and passed through a 300-500 mesh sieve.

[0016] Furthermore, in step S2, the diameter of the SPS sintering mold is 20 mm; during sintering, the axial pressure is 50-70 MPa, and the sintering time is 15-20 min at a temperature of 1400-1600°C.

[0017] Furthermore, in step S2, the sintering process is: heating from room temperature to 1200°C at 50°C / min, then heating to 1400-1600°C at 20°C / min and keeping at that temperature for 15-20 min.

[0018] The present invention also provides the use of the above-mentioned high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion in the preparation of thermal barrier coating materials.

[0019] The present invention has the following beneficial effects:

[0020] 1. The high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance of the present invention is specifically a new type of rare earth niobium tantalate ceramic material, and its chemical formula is (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4; The roles of the five rare earth elements in the A position are: Y2O3 (yttrium oxide): commonly used to stabilize zirconia (YSZ), a classic material for thermal barrier coatings, forming a stable cubic or tetragonal phase structure to improve phase stability. Therefore, Y2O3 is selected to stabilize the structure. Gd2O3 (gadolinium oxide), Dy2O3 (dysprosium oxide): Gd 3+ and Dy 3+ The ionic radius is larger, which can introduce more lattice distortion and enhance the high entropy effect. Er2O3 (Er2O3 oxide): Er2O3 doping has a certain restriction effect on its crystal growth and can improve the sintering resistance of the material. Yb2O3 (Ytterbium oxide): Yb 3+ The smaller ionic radius is used to increase the system's configurational entropy, further modulate lattice distortion, and enhance the solid solution strengthening effect. Selecting five rare earth elements with similar ionic radii promotes sintering and facilitates the formation of a uniform solid solution. Ta is added to the B site because the Nb phase is unstable and prone to phase transformation.

[0021] 2. The ceramic body preparation process eliminates the need for granulation, calcination, or the addition of a binder. Direct SPS sintering is employed, significantly shortening sintering time and reducing sintering temperatures compared to solid-phase reaction methods. The resulting ceramic exhibits fine crystals, excellent toughness, and superior resistance to CMAS corrosion. When the rare earth high-entropy tantalate ceramic material comes into contact with molten sediments, the Ta element in the material reacts with the Ca infiltrating from the molten sediments to form a dense corrosion reaction layer, Ca2Ta2O7, which isolates the CMAS ceramic matrix. This corrosion reaction layer prevents further penetration of molten sediments into the ceramic layer, reducing corrosion depth. The material can be used in the preparation of thermal barrier coatings.

[0022] 3. SPS sintering effectively prevents excessive grain growth and eliminates the need for any sintering aids. This significantly shortens sintering time, reduces costs, and significantly increases ceramic density. The high-entropy ceramic material provided by this invention exhibits excellent fracture toughness and resistance to CMAS corrosion. This ceramic material can provide thermal protection and extend the service life of hot-end components in major equipment such as aircraft engines and gas turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1XRD patterns of high-entropy ceramic materials with high fracture toughness and CMAS corrosion resistance obtained in Examples 1 to 4; (a) is the XRD pattern of the high-entropy ceramic material, and (b) is an enlarged view of the characteristic peak at 46°-50°;

[0024] Figure 2 The electron microscope scanning and energy spectrum element distribution diagram of the high entropy ceramic materials obtained in Examples 1 to 4 and Comparative Example 1;

[0025] Figure 3 The grain and element distribution diagrams of the products obtained in Examples 1 to 4 after thermal etching;

[0026] Figure 4 The cross-sectional electron microscopy images of the samples of Examples 1 to 4 and Comparative Example 1 after CMAS corrosion for 1 h are shown;

[0027] Figure 5 These are cross-sectional electron microscope images of the samples of Examples 1 to 4 and Comparative Example 1 after CMAS corrosion for 20 h. DETAILED DESCRIPTION

[0028] The principles and features of the present invention are described below. The examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. In the examples, where specific conditions are not specified, conventional conditions or manufacturer-recommended conditions were used. Reagents or instruments used where the manufacturer is not specified are conventional products that can be purchased commercially.

[0029] Example 1

[0030] A high entropy ceramic material with high fracture toughness and CMAS corrosion resistance, its chemical formula is (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4;x=1,y=0.

[0031] The method for preparing the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion comprises the following steps:

[0032] S1. Oxide powders (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, and Nb2O5 powder) with a particle size of 1-3 μm were placed in zirconia crucibles and calcined at 900°C for 2.5 h to remove moisture and organic impurities from each oxide powder, so that the purity of each oxide powder was ≥99.99%. Then, the calcined oxide powders were placed in a zirconia ball mill with a molar ratio of Gd, Dy, Er, Yb, Y, and Nb of 0.2:0.2:0.2:0.2:0.2:1, and anhydrous ethanol and zirconia balls were added and ball milled at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powder, and anhydrous ethanol was 2:1:0.6. Slurry A was obtained.

[0033] S2. Slurry A was dried at 80 °C for 18 h, ground for 6 min, passed through a 400-mesh sieve, and then placed in an SPS sintering mold. The axial pressure was 50 MPa, and the sintering furnace was heated from room temperature to 1200 °C at 50 °C / min, then heated to 1600 °C at 20 °C / min, kept at this temperature for 15 min, and cooled to room temperature to obtain a ceramic block.

[0034] S3. The ceramic block is placed in a muffle furnace and annealed at 1600 °C for 2 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0035] Example 2

[0036] A high entropy ceramic material with high fracture toughness and CMAS corrosion resistance, its chemical formula is (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4;x=0.5,y=0.5.

[0037] The method for preparing the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion comprises the following steps:

[0038] S1. Oxide powders (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder and Ta2O5 powder) with a particle size of 1-3 μm were placed in zirconia crucibles respectively and calcined at 800°C for 3 h to remove moisture and organic impurities in each oxide powder so that the purity of each oxide powder was ≥99.99%; then, the calcined oxide powders were placed in a zirconia ball mill according to the molar ratio of Gd, Dy, Er, Yb, Y, Nb and Ta being 0.2:0.2:0.2:0.2:0.2:0.5:0.5, and anhydrous ethanol and zirconia balls were added and ball milled at 300 rpm for 12 h. The mass ratio of zirconia balls, oxide powder and anhydrous ethanol was 2:1:0.5; thus, slurry A was obtained;

[0039] S2. Slurry A was dried at 70 °C for 12 h, ground for 5 min, passed through a 300-mesh sieve, and then placed in an SPS sintering mold. The axial pressure was 50 MPa, and the sintering furnace was heated from room temperature to 1200 °C at 50 °C / min, then heated to 1600 °C at 20 °C / min, kept at this temperature for 15 min, and cooled to room temperature to obtain a ceramic block.

[0040] S3. The ceramic block is placed in a muffle furnace and annealed at 1600 °C for 3 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0041] Example 3

[0042] A high entropy ceramic material with high fracture toughness and CMAS corrosion resistance, its chemical formula is (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4;x=0.2,y=0.8.

[0043] The method for preparing the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion comprises the following steps:

[0044] S1. Oxide powders (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder, and Ta2O5 powder) with a particle size of 1-3 μm were placed in zirconia crucibles respectively and calcined at 1000°C for 2 h to remove moisture and organic impurities from each oxide powder so that the purity of each oxide powder was ≥99.99%; then, the calcined oxide powders were placed in a zirconia ball mill according to the molar ratio of Gd, Dy, Er, Yb, Y, Nb, and Ta being 0.2:0.2:0.2:0.2:0.2:0.2:0.8, and anhydrous ethanol and zirconia balls were added and ball milled at 400 rpm for 48 h. The mass ratio of zirconia balls, oxide powder, and anhydrous ethanol was 2:1:0.6; thus, slurry A was obtained;

[0045] S2. Slurry A was dried at 90 °C for 24 h, ground for 7 min, passed through a 500-mesh sieve, and then placed in an SPS sintering mold. The axial pressure was 50 MPa, and the sintering furnace was heated from room temperature to 1200 °C at 50 °C / min, then heated to 1600 °C at 20 °C / min, kept at this temperature for 15 min, and cooled to room temperature to obtain a ceramic block.

[0046] S3. The ceramic block is placed in a muffle furnace and annealed at 1600 °C for 4 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0047] Example 4

[0048] A high entropy ceramic material with high fracture toughness and CMAS corrosion resistance, its chemical formula is (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4;x=0,y=1.

[0049] The method for preparing the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion comprises the following steps:

[0050] S1. Oxide powders (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, and Ta2O5 powder) with a particle size of 1-3 μm were placed in zirconia crucibles and calcined at 900°C for 2.5 h to remove moisture and organic impurities from each oxide powder, so that the purity of each oxide powder was ≥99.99%. Then, the calcined oxide powders were placed in a zirconia ball mill according to a molar ratio of Gd, Dy, Er, Yb, Y, and Ta of 0.2:0.2:0.2:0.2:0.2:1, and anhydrous ethanol and zirconia balls were added and ball milled at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powder, and anhydrous ethanol was 2:1:0.6. Slurry A was obtained.

[0051] S2. Slurry A was dried at 80 °C for 18 h, ground for 6 min, passed through a 400-mesh sieve, and then placed in an SPS sintering mold. The axial pressure was 50 MPa, and the sintering furnace was heated from room temperature to 1200 °C at 50 °C / min, then heated to 1600 °C at 20 °C / min, kept at this temperature for 15 min, and cooled to room temperature to obtain a ceramic block.

[0052] S3. Place the ceramic block in a muffle furnace and anneal at 1600 °C for 5 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0053] Comparative Example 1

[0054] A ceramic material with the chemical formula (ZrO2) 0.93 (Y2O3) 0.07 .

[0055] The method for preparing the above ceramic material comprises the following steps:

[0056] S1. ZrO2 powder and Y2O3 powder with a particle size of 1-3 μm were placed in zirconia crucibles respectively and calcined at 900°C for 2.5 h to remove moisture and organic impurities from each oxide powder so that the purity of each oxide powder was ≥99.99%. The calcined powders were then placed in a zirconia ball mill with a mass ratio of ZrO2 powder to Y2O3 powder of 93:7. Anhydrous ethanol and zirconia balls were added and ball milled at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powder, and anhydrous ethanol was 2:1:0.6. Slurry A was obtained.

[0057] S2. Slurry A was dried at 80 °C for 18 h, ground for 6 min, passed through a 400-mesh sieve, and then placed in an SPS sintering mold. The axial pressure was 50 MPa, and the sintering furnace was heated from room temperature to 1200 °C at 50 °C / min, then heated to 1400 °C at 20 °C / min, kept at this temperature for 15 min, and cooled to room temperature to obtain a ceramic block.

[0058] S3. Place the ceramic block in a muffle furnace and anneal at 1600°C for 5 h to obtain a ceramic material.

[0059] Comparative Example 2

[0060] A ceramic material with the chemical formula GdNbO4.

[0061] The method for preparing the above ceramic material comprises the following steps:

[0062] S1. Gd2O3 powder and Nb2O5 powder with a particle size of 1-3 μm were placed in zirconia crucibles respectively and calcined at 900°C for 2.5 h to remove moisture and organic impurities from each oxide powder, so that the purity of each oxide powder was ≥99.99%. Then, the calcined powders were placed in a zirconia ball mill with a molar ratio of Gd to Nb of 1:1, and anhydrous ethanol and zirconia balls were added and ball milled at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powder and anhydrous ethanol was 2:1:0.6. Slurry A was obtained.

[0063] S2. Slurry A was dried at 80 °C for 18 h, ground for 6 min, passed through a 400-mesh sieve, and then placed in an SPS sintering mold. The axial pressure was 50 MPa, and the sintering furnace was heated from room temperature to 1200 °C at 50 °C / min, then heated to 1400 °C at 20 °C / min, kept at this temperature for 15 min, and cooled to room temperature to obtain a ceramic block.

[0064] S3. Place the ceramic block in a muffle furnace and anneal at 1600°C for 5 h to obtain a ceramic material.

[0065] Comparative Example 3

[0066] A ceramic material with the chemical formula DyTaO4.

[0067] The method for preparing the above ceramic material comprises the following steps:

[0068] S1. Dy2O3 powder and Ta2O5 powder with a particle size of 1-3 μm were placed in zirconia crucibles respectively and calcined at 900°C for 2.5 h to remove moisture and organic impurities from each oxide powder, so that the purity of each oxide powder was ≥99.99%. Then, the calcined powders were placed in a zirconia ball mill with a molar ratio of Dy to Ta of 1:1, and anhydrous ethanol and zirconia balls were added and ball milled at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powder and anhydrous ethanol was 2:1:0.6 to obtain slurry A.

[0069] S2. Slurry A was dried at 80 °C for 18 h, ground for 6 min, passed through a 400-mesh sieve, and then placed in an SPS sintering mold. The axial pressure was 50 MPa, and the sintering furnace was heated from room temperature to 1200 °C at 50 °C / min, then heated to 1400 °C at 20 °C / min, kept at this temperature for 15 min, and cooled to room temperature to obtain a ceramic block.

[0070] S3. Place the ceramic block in a muffle furnace and anneal at 1600°C for 5 h to obtain a ceramic material.

[0071] Test example

[0072] 1. Structural testing

[0073] The products obtained in Examples 1 to 4 were subjected to X-ray diffraction test, and the characteristic peak at 46°-50° was amplified. The results are as follows: Figure 1 shown.

[0074] Depend on Figure 1 As can be seen, the ceramic material obtained in Example 4 exhibits an additional characteristic diffraction peak at approximately 47.4°, while the ceramic materials obtained in Examples 1-3 do not. Furthermore, Examples 1-4 are all monoclinic phases, with no apparent impurity phases present. This demonstrates that the SPS rapid sintering method successfully yields uniform, single-phase, high-entropy solid solution ceramics.

[0075] The microstructure and energy spectrum element distribution of the products obtained in Examples 1 to 4 and Comparative Example 1 were observed using a scanning electron microscope. The results are as follows: Figure 2 shown.

[0076] Depend on Figure 2 As can be seen, the high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance prepared by the present invention has a relatively dense structure, although different ceramic blocks with different compositions still have varying degrees of porosity on the surface. The high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance prepared by the present invention has a uniform distribution of elements without aggregation.

[0077] The products obtained in Examples 1 to 4 were subjected to thermal corrosion tests, and the results are as follows: Figure 3 shown.

[0078] Depend on Figure 3 As can be seen, the grain boundaries between the ceramics after thermal corrosion are clear, irregularly polygonal in shape, with a small amount of pores visible. Notably, the grain surfaces exhibit parallel stripes, representing ferroelastic domains. With the gradual addition of Ta, the ceramic grains become increasingly finer and densely packed.

[0079] 2. CMAS corrosion resistance test

[0080] 1. Preparation of CMAS powder

[0081] The oxide powders were weighed according to the molar ratio of CaO, MgO, Al2O3 and SiO2 of 33:9:13:45 and placed in a mortar. The oxide powders were thoroughly ground until the oxides were evenly mixed. The mixed oxide powders were then placed in an alumina crucible and sintered in a high-temperature furnace at 1400°C for 2 h. The mixture was then cooled in the furnace. The sintered powder was ground again and passed through a 500-mesh sieve. The sieved powder was the CMAS powder.

[0082] 2. The surfaces of the samples obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were ground and polished, and then the sample surfaces were cleaned with alcohol. The prepared CMAS powder was then heated to 15 mg / cm 3 The coating amount was evenly coated on the surface of each sample, and then placed in an alumina crucible and placed in a sintering furnace for high-temperature reaction. The corrosion temperature was 1300 ° C, and the corrosion time was set to 1 h and 20 h, respectively. After the corrosion was completed, the corrosion area of ​​the sample was characterized by XRD, SEM and EDS, and then the corrosion depth of each sample was compared to determine the corrosion quality. Since CMAS directly invaded the ceramic substrate in Example 1 and Example 2 and did not generate a corrosion reaction layer, it was not involved in the corrosion depth comparison; the cross-sectional electron microscope scanning images of each sample after CMAS corrosion for 1 h and 20 h are shown as follows: Figure 4 and as shown in Figure 5.

[0083] Depend on Figure 4As shown in Figure 5, the corrosion reaction layer formed between the ceramic layer and the CMAS layer in the samples of Examples 1-4 is composed of dense Ca2Ta2O7, as determined by EDS spectroscopy. In the example samples, the CMAS element is present only in the corrosion reaction layer and the CMAS residual layer, preventing further penetration of CMAS into the ceramic layer. Table 1 summarizes the depth of the corrosion layer or corrosion reaction layer for the example and comparative examples. The graphs and tables show that the corrosion depths and corrosion rates of the samples of Examples 1-4 are lower than those of Examples 1-4, demonstrating that the example samples exhibit excellent resistance to CMAS corrosion. CMAS does not penetrate the ceramic layer during the entire corrosion process.

[0084] Table 1 Statistics of the depth of corrosion layer or corrosion reaction layer of samples

[0085]

[0086] 3. Hardness test

[0087] The ceramic blocks obtained from Examples 1-4 and Comparative Examples 1-3 were ground and polished, and then subjected to a load of 9.8 N using a micro-Vickers hardness tester to obtain hardness values. Each sample was measured 10 times, and the maximum and minimum values ​​were removed. The average of the remaining values ​​was used as the final hardness value. The results are shown in Table 2.

[0088] Table 2 Average hardness statistics

[0089]

[0090] As can be seen from Table 2, the hardness of Examples 1 to 4 is higher than that of Comparative Examples 2 to 3, indicating that the hardness of rare earth niobium tantalate can be increased by using the method provided by the invention.

[0091] 4. Fracture toughness test

[0092] The ceramic blocks obtained in Examples 1-4 and Comparative Examples 1-3 were polished, and the fracture toughness of the niobium tantalate ceramics was calculated using the indentation method. Taking the ceramic blocks obtained in Examples 1-4 and Comparative Examples 1-3 as examples, the specific method is as follows: the polished ceramic blocks were indented with a Vickers hardness tester at a certain load (F) to obtain the hardness (Hv), and this was performed 10 times for each sample. Then, from the scanning electron microscope image, half of the indentation diagonal length (a) and the half crack length (c) measured from the middle of the indentation to the crack tip were obtained. The formula:

[0093] ;

[0094] The fracture toughness was calculated by taking the average value of 10 times for each sample. The calculation results are shown in Table 3.

[0095] Table 3 Average fracture toughness test results

[0096]

[0097] As can be seen from Table 3, Examples 1 to 4 have higher toughness than Comparative Examples 2 to 3, indicating that the method provided by the invention can improve the toughness of rare earth niobium tantalate.

[0098] 5. Young's modulus test

[0099] The ceramic blocks obtained in Examples 1-4 and Comparative Examples 1-3 were polished and then subjected to Young's modulus testing using nanoindentation. The test parameters were an applied load of 50 mN, a dwell time of 10 s, and a Bosch indenter. To improve the accuracy of the test results, multiple tests were performed on ceramics with different compositions to obtain multiple sets of data and reduce errors. Specific Young's moduli are shown in Table 4.

[0100] Table 4 Young's modulus test results

[0101]

[0102] As shown in Table 4, the Young's modulus of the products of Examples 1 to 4 is improved with the addition of tantalum. The Young's modulus of the products of Examples 2 to 4 is better than that of Example 1 and Comparative Examples 2 to 3.

[0103] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high entropy ceramic material with high fracture toughness and resistance to CMAS corrosion, characterized in that: Its chemical formula is (Gd 0.2 Dy 0.2 Er 0.2 Yb 0.2 Y 0.2 )(Nb x Ta y )O4; Among them, 0≤x≤1, 0≤y≤1, and x+y=1, and the density is ≥95%.

2. The method for preparing the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 1, characterized in that: The following steps are involved: S1. Mixing the pretreated oxide powder and a dispersant, and ball milling to obtain slurry A; the oxide powder includes Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder and Ta2O5 powder; S2, drying, grinding and sieving the slurry A in sequence, then sintering it in an SPS sintering mold, and cooling it to room temperature to obtain a ceramic block; S3. Annealing the ceramic block at 1300-1600 °C for 2-5 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

3. The method for preparing a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that: In step S1, during pretreatment, the oxide powder is calcined at 800-1000° C. for 2-3 h.

4. The method for preparing a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that: In step S1, the oxide powder has a particle size of 1-3 μm and a purity of ≥99.99%.

5. The method for preparing a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that: In step S1, the dispersant is anhydrous ethanol; the mass ratio of the oxide powder to the dispersant is 1:0.5-0.

6.

6. The method for preparing a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that: In step S1, ball milling is performed at 300-400 rpm for 12-48 h.

7. The method for preparing a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that: In step S2, the product is dried at 70-90° C. for 12-24 h, ground for 5-7 min, and passed through a 300-500 mesh sieve.

8. The method for preparing a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that: In step S2, the diameter of the SPS sintering mold is 20 mm; during sintering, the axial pressure is 50-70 MPa, and the sintering time is 15-20 min at a temperature of 1400-1600°C.

9. The method for preparing a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, wherein: In step S2, the sintering process is: heating from room temperature to 1200°C at 50°C / min, then heating to 1400-1600°C at 20°C / min and keeping at that temperature for 15-20 min.

10. Use of the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 1 in the preparation of thermal barrier coating materials.

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