High-entropy ceramic material with high fracture toughness and CMAS corrosion resistance and preparation method thereof

Abstract

The 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 chemical formula of the high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance is (Gd < 0.2 > Dy < 0.2 > Er < 0.2 > Yb < 0.2 > Y < 0.2 >) (Nb < x > Tay) O4, wherein 0 < = x < = 1, 0 < = y < = 1, x + y = 1, and density > = 95%. The invention also provides a preparation method and application of the high-entropy ceramic material with high fracture toughness and CMAS corrosion resistance. The high-entropy ceramic material has excellent high fracture toughness and CMAS corrosion resistance, and the problems that in the prior art, a thermal barrier coating material is not ideal in fracture toughness, poor in CMAS corrosion resistance and the like are effectively solved.

Description

Technical Field

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

[0002] The technology of thermal barrier coatings (TBCs) is a key technology to improve the temperature-bearing capacity of aeroengines. However, with the continuous increase in the operating temperature of aeroengines, the corrosion of molten environmental deposits (CMAS) has gradually become the main form of thermal barrier coating failure. Traditional thermal barrier coating materials, such as yttria-stabilized zirconia (YSZ), have defects such as premature coating failure and insufficient temperature-bearing capacity, and can no longer meet the requirements of aeroengines for high-temperature oxidation resistance, thermal shock resistance, and external corrosion resistance. Therefore, it is urgent to develop new thermal barrier coating materials with excellent comprehensive properties such as low thermal conductivity, high hardness, high toughness, and high-temperature corrosion resistance.

[0003] Rare earth tantalates or niobates (RETa / NbO4) are a new type of potential thermal barrier coating materials. However, niobates undergo a phase change at about 800 °C, and tantalates undergo a phase change at about 1300 - 1400 °C, and the structure is not stable enough; the previous research on the preparation of high-entropy rare earth niobates also shows poor high-temperature phase stability, with a phase change occurring at about 850 °C, and at the same time, its resistance to CMAS corrosion is poor. Therefore, in the present invention, tantalum elements are added to rare earth niobates to improve their phase stability while enhancing their mechanical properties and resistance to CMAS corrosion. 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 resistance to CMAS corrosion and a preparation method thereof. The high-entropy ceramic material has excellent high fracture toughness and resistance to CMAS corrosion, effectively solving the problems such as unsatisfactory fracture toughness and weak resistance to CMAS corrosion 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: Provide a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion, 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; wherein, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, and x + y = 1, and the relative density ≥ 95%.

[0006] Further, y = 0.5, 0.8.

[0007] The present invention also provides a method for preparing the above high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion, comprising the following steps: S1. Mix the pretreated oxide powders and a dispersant, and ball-mill to obtain slurry A; the oxide powders include Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder, and Ta2O5 powder; S2. Subject slurry A to drying, grinding, and sieving in sequence, then place it in an SPS sintering mold for sintering, and cool to room temperature to obtain a ceramic block; S3. Anneal the ceramic block at a temperature of 1300 - 1600 °C for 2 - 5 h to obtain the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0008] Further, in step S1, during pretreatment, calcine the oxide powders at a temperature of 800 - 1000 °C for 2 - 3 h.

[0009] Further, in step S1, the particle size of the oxide powders is 1 - 3 μm, and the purity ≥ 99.99%.

[0010] Further, in step S1, the dispersant is anhydrous ethanol; the mass ratio of the oxide powders to the dispersant is 1:0.5 - 0.6.

[0011] Further, in step S1, ball-mill at 300 - 400 rpm for 12 - 48 h.

[0012] Further, in step S2, dry at a temperature of 70 - 90 °C for 12 - 24 h, grind for 5 - 7 min, and sieve through a 300 - 500 mesh sieve.

[0013] Further, in step S2, the diameter of the SPS sintering mold is 20 mm; during sintering, the axial pressure is 50 - 70 MPa, and sinter at a temperature of 1400 - 1600 °C for 15 - 20 min.

[0014] Further, in step S2, the sintering process is: heat from room temperature to 1200 °C at a rate of 50 °C / min, and then heat to a temperature of 1400 - 1600 °C at a rate of 20 °C / min and hold for 15 - 20 min.

[0015] The present invention also provides the application of the above high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion in the preparation of thermal barrier coating materials.

[0016] The present invention has the following beneficial effects: 1. The high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion of the present invention is specifically a novel rare-earth niobate 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 functions of the five rare-earth elements in the A site are as follows: Y2O3 (yttrium oxide): commonly used to stabilize zirconia (YSZ), as 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): The ionic radii of Gd 3+ and Dy 3+ are relatively large, which can introduce more lattice distortions and enhance the high-entropy effect. Er2O3 (erbium oxide): The doping of Er2O3 has a certain restrictive effect on its crystal growth and can improve the anti-sintering property of the material. Yb2O3 (ytterbium oxide): The ionic radius of Yb 3+ is relatively small, which is used to increase the configurational entropy of the system, further adjust the lattice distortion, and enhance the solid-solution strengthening effect. Selecting five rare-earth elements with similar ionic radii can promote sintering and easily form a uniform solid solution. Ta is added to the B site because the phase stability of Nb is too poor and it is easy to produce phase transformation.

[0017] 2. In the process of preparing the ceramic green body, granulation, calcination, and addition of binders are not required. SPS sintering is directly used, which greatly shortens the sintering time. At the same time, the sintering temperature is reduced compared with the solid-state reaction method. The prepared ceramic has fine grains, good toughness, and excellent resistance to CMAS corrosion. When the rare-earth high-entropy tantalate ceramic material contacts the molten environmental sediment, the Ta element contained in the material reacts with the infiltrated Ca in the molten environmental sediment to form a dense corrosion reaction layer of Ca2Ta2O7, thereby isolating the CMAS ceramic matrix. The corrosion reaction layer prevents the molten environmental sediment from further infiltrating into the ceramic layer and reduces the corrosion depth; it can be used to prepare thermal barrier coating materials.

[0018] 3. SPS sintering can effectively resist the excessive growth of grains, and no sintering aids need to be added. The sintering time is greatly shortened, the cost is low, and the ceramic density is greatly improved. The high-entropy ceramic material provided by the present invention has excellent high fracture toughness and resistance to CMAS corrosion. This ceramic material can provide heat protection and extend the service life for the hot-end components in the fields of aero-engines, gas turbines and other major national weapons. Description of the Drawings

[0019] Figure 1XRD patterns of the high-entropy ceramic materials with high fracture toughness and resistance to CMAS corrosion obtained in Examples 1-4; (a) is the XRD pattern of the high-entropy ceramic material, and (b) is the enlarged view of the characteristic peaks at 46°-50°; Figure 2 SEM and energy spectrum element distribution maps of the products of high-entropy ceramic materials obtained in Examples 1-4 and Comparative Example 1; Figure 3 Maps of grains and elements after thermal etching of the products obtained in Examples 1-4; Figure 4 Cross-sectional SEM images of the samples of Examples 1-4 and Comparative Example 1 after CMAS corrosion for 1 h; Figure 5 Cross-sectional SEM images of the samples of Examples 1-4 and Comparative Example 1 after CMAS corrosion for 20 h. Detailed implementation manners

[0020] The principles and features of the present invention are described below. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. For those not specified in the examples, the operations are carried out under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not indicated with the manufacturer are all conventional products that can be obtained through commercial purchase.

[0021] Example 1 A high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion, whose 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.

[0022] The preparation method of the above high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion includes the following steps: S1. Oxide powders with a particle size of 1-3 μm (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder) are respectively placed in a zirconia crucible and calcined at 900 °C for 2.5 h to remove moisture and organic impurities in each oxide powder, so that the purity of each oxide powder is ≥99.99%; then, according to the molar ratio of Gd, Dy, Er, Yb, Y and Nb of 0.2:0.2:0.2:0.2:0.2:1, the calcined oxide powders are placed in a zirconia ball milling tank, and anhydrous ethanol and zirconia balls are added and ball milled at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powders and anhydrous ethanol is 2:1:0.6; slurry A is obtained; S2. Dry the slurry A at 80 °C for 18 h, grind it for 6 min, pass it through a 400-mesh sieve, then place it in an SPS sintering mold. Apply an axial pressure of 50 MPa. The sintering furnace is heated from room temperature to 1200 °C at a rate of 50 °C / min, then heated to 1600 °C at a rate of 20 °C / min and held at this temperature for 15 min, and then cooled to room temperature to obtain a ceramic block; S3. Place the ceramic block in a muffle furnace and anneal it at 1600 °C for 2 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0023] Example 2 A high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion, whose 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.

[0024] The preparation method of the above high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion includes the following steps: S1. Place oxide powders with a particle size of 1 - 3 μm (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder, and Ta2O5 powder) in zirconia crucibles respectively, and calcine them at 800 °C for 3 h to remove moisture and organic impurities in each oxide powder, so that the purity of each oxide powder is ≥99.99%; then, 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, place the calcined oxide powders in a zirconia ball mill tank, add anhydrous ethanol and zirconia balls, and ball mill them at 300 rpm for 12 h. The mass ratio of zirconia balls, oxide powders, and anhydrous ethanol is 2:1:0.5; obtain slurry A; S2. Dry the slurry A at 70 °C for 12 h, grind it for 5 min, pass it through a 300-mesh sieve, then place it in an SPS sintering mold. Apply an axial pressure of 50 MPa. The sintering furnace is heated from room temperature to 1200 °C at a rate of 50 °C / min, then heated to 1600 °C at a rate of 20 °C / min and held at this temperature for 15 min, and then cooled to room temperature to obtain a ceramic block; S3. Place the ceramic block in a muffle furnace and anneal it at 1600 °C for 3 h to obtain a high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0025] Example 3 A high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion, whose 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.

[0026] The preparation method of the above high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion includes the following steps: S1. Place oxide powders with a particle size of 1 - 3 μm (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, Nb2O5 powder, and Ta2O5 powder) in a zirconia crucible respectively, and calcine at 1000 °C for 2 h to remove moisture and organic impurities in each oxide powder, so that the purity of each oxide powder is ≥99.99%; then, 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, place the calcined oxide powders in a zirconia ball milling tank, add anhydrous ethanol and zirconia balls, and ball mill at 400 rpm for 48 h. The mass ratio of zirconia balls, oxide powders, and anhydrous ethanol is 2:1:0.6; obtain slurry A; S2. Dry slurry A at 90 °C for 24 h, grind for 7 min, pass through a 500-mesh sieve, then place it in an SPS sintering mold, with an axial pressure of 50 MPa. The sintering furnace is heated from room temperature to 1200 °C at a rate of 50 °C / min, and then heated to 1600 °C at a rate of 20 °C / min and held for 15 min, and then cooled to room temperature to obtain a ceramic block; S3. Place the ceramic block in a muffle furnace and anneal at 1600 °C for 4 h to obtain the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0027] Example 4 A high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion, whose 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.

[0028] The preparation method of the above high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion includes the following steps: S1. Place oxide powders with a particle size of 1 - 3 μm (Gd2O3 powder, Dy2O3 powder, Er2O3 powder, Yb2O3 powder, Y2O3 powder, and Ta2O5 powder) in zirconia crucibles respectively, and calcine them at 900 °C for 2.5 h to remove moisture and organic impurities in each oxide powder, so that the purity of each oxide powder is ≥99.99%; then, according to the molar ratio of Gd, Dy, Er, Yb, Y, and Ta being 0.2:0.2:0.2:0.2:0.2:1, place the calcined oxide powders in a zirconia ball milling tank, add anhydrous ethanol and zirconia balls, and ball mill them at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powders, and anhydrous ethanol is 2:1:0.6; obtain slurry A; S2. Dry slurry A at 80 °C for 18 h, grind it for 6 min, sieve it through a 400 - mesh sieve, then place it in an SPS sintering mold, with an axial pressure of 50 MPa. The sintering furnace heats up from room temperature to 1200 °C at a rate of 50 °C / min, and then heats up to 1600 °C at a rate of 20 °C / min and holds for 15 min, and then cools to room temperature to obtain a ceramic block; S3. Place the ceramic block in a muffle furnace and anneal it at 1600 °C for 5 h to obtain a high - entropy ceramic material with high fracture toughness and resistance to CMAS corrosion.

[0029] Comparative Example 1 A ceramic material with the chemical formula (ZrO2) 0.93 (Y2O3) 0.07 .

[0030] The preparation method of the above - mentioned ceramic material includes the following steps: S1. Place ZrO2 powder and Y2O3 powder with a particle size of 1 - 3 μm in zirconia crucibles respectively, and calcine them at 900 °C for 2.5 h to remove moisture and organic impurities in each oxide powder, so that the purity of each oxide powder is ≥99.99%; then, according to the mass ratio of ZrO2 powder and Y2O3 powder being 93:7, place the calcined powders in a zirconia ball milling tank, add anhydrous ethanol and zirconia balls, and ball mill them at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powders, and anhydrous ethanol is 2:1:0.6; obtain slurry A; S2. Dry slurry A at 80 °C for 18 h, grind it for 6 min, sieve it through a 400 - mesh sieve, then place it in an SPS sintering mold, with an axial pressure of 50 MPa. The sintering furnace heats up from room temperature to 1200 °C at a rate of 50 °C / min, and then heats up to 1400 °C at a rate of 20 °C / min and holds for 15 min, and then cools to room temperature to obtain a ceramic block; S3. Place the ceramic block in a muffle furnace and anneal it at 1600 °C for 5 h to obtain the ceramic material.

[0031] Comparative Example 2 A ceramic material with the chemical formula GdNbO4.

[0032] The preparation method of the above-mentioned ceramic material includes the following steps: S1. Respectively place Gd2O3 powder and Nb2O5 powder with a particle size of 1 - 3 μm in a zirconia crucible, and calcine them at 900 °C for 2.5 h to remove the moisture and organic impurities in each oxide powder, so that the purity of each oxide powder is ≥99.99%; then, according to the molar ratio of Gd and Nb being 1:1, place the calcined powder in a zirconia ball milling tank, add anhydrous ethanol and zirconia balls, and ball mill at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powder, and anhydrous ethanol is 2:1:0.6; obtain slurry A; S2. Dry slurry A at 80 °C for 18 h, grind it for 6 min, pass it through a 400-mesh sieve, then place it in an SPS sintering mold, with an axial pressure of 50 MPa. The sintering furnace is heated from room temperature to 1200 °C at a rate of 50 °C / min, and then heated to 1400 °C at a rate of 20 °C / min and held for 15 min, and then cooled to room temperature to obtain the ceramic block; S3. Place the ceramic block in a muffle furnace and anneal it at 1600 °C for 5 h to obtain the ceramic material.

[0033] Comparative Example 3 A ceramic material with the chemical formula DyTaO4.

[0034] The preparation method of the above-mentioned ceramic material includes the following steps: S1. Respectively place Dy2O3 powder and Ta2O5 powder with a particle size of 1 - 3 μm in a zirconia crucible, and calcine them at 900 °C for 2.5 h to remove the moisture and organic impurities in each oxide powder, so that the purity of each oxide powder is ≥99.99%; then, according to the molar ratio of Dy and Ta being 1:1, place the calcined powder in a zirconia ball milling tank, add anhydrous ethanol and zirconia balls, and ball mill at 350 rpm for 24 h. The mass ratio of zirconia balls, oxide powder, and anhydrous ethanol is 2:1:0.6; obtain slurry A; S2. Dry the slurry A at 80 °C for 18 h, grind it for 6 min, sieve it through a 400-mesh sieve, then place it in an SPS sintering mold. Apply an axial pressure of 50 MPa. Heat the sintering furnace from room temperature to 1200 °C at a rate of 50 °C / min, then heat it to 1400 °C at a rate of 20 °C / min and hold for 15 min, and cool it to room temperature to obtain a ceramic block; S3. Place the ceramic block in a muffle furnace and anneal it at 1600 °C for 5 h to obtain a ceramic material.

[0035] Test Example I. Structure Test Perform X-ray diffraction tests on the products obtained in Examples 1-4, and magnify the characteristic peaks at 46°-50°. The results are as Figure 1 shown.

[0036] As can be seen from Figure 1 , there is an additional characteristic diffraction peak at about 47.4° for the ceramic material obtained in Example 4, while there is no such peak for the ceramic materials obtained in Examples 1-3. Moreover, Examples 1-4 are all in the monoclinic phase and there are no obvious impurity phases, indicating that a single-phase high-entropy solid solution ceramic with uniform composition has been successfully obtained by the SPS rapid sintering method.

[0037] Use a scanning electron microscope to observe the microtopography and energy spectrum element distribution of the products obtained in Examples 1-4 and Comparative Example 1. The results are as Figure 2 shown.

[0038] As can be seen from Figure 2 , the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion prepared in the present invention has a relatively dense structure, and there are different degrees of porosity on the surfaces of ceramic blocks with different compositions. The elements in the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion prepared in the present invention are evenly distributed and there is no aggregation.

[0039] Perform a thermal corrosion experiment on the products obtained in Examples 1-4. The results are as Figure 3 shown.

[0040] As can be seen from Figure 3 , the grain boundaries between the ceramic grains after thermal corrosion are clear, and the shape is an irregular polygon. A small amount of pores can be seen. It is worth noting that there are parallel stripe morphologies on the grain surfaces, which are ferroelastic domain states. With the gradual addition of Ta element, the ceramic grains become finer and more densely arranged.

[0041] II. CMAS Corrosion Resistance Test 1. Prepare CMAS powder Weigh each oxide powder according to the molar ratio of CaO, MgO, Al2O3 and SiO2 being 33:9:13:45 and place it in a mortar. Grind the oxide powder thoroughly until the oxides are evenly mixed. Then place the mixed oxide powder in an alumina crucible, put it into a high-temperature furnace, keep it sintered at 1400 °C for 2 h, and then cool it with the furnace. The sintered powder is ground again and passed through a 500-mesh sieve. The powder after sieving is the CMAS powder.

[0042] 2. Polish and grind the surfaces of the samples obtained in Examples 1 - 4 and Comparative Examples 1 - 3, then clean the sample surfaces with alcohol. Then, uniformly coat the prepared CMAS powder on the surfaces of each sample at a coating amount of 15 mg / cm 3 . Then put it into an alumina crucible and place it in a sintering furnace for high-temperature reaction. The corrosion temperature is 1300 °C, and the corrosion times are set to 1 h and 20 h respectively. After the corrosion is completed, characterize the corrosion area of the sample by XRD, SEM and EDS, and then compare the corrosion depths of each sample to determine the pros and cons of corrosion resistance. Since no corrosion reaction layer is formed when CMAS directly invades the ceramic substrate in Examples 1 and 2, they are not involved in the comparison of corrosion depth. The cross-sectional SEM images of each sample after CMAS corrosion for 1 h and 20 h are respectively as Figure 4 shown in Figure 5.

[0043] As can be seen from Figure 4 Figure 5, in the samples of Examples 1 - 4, a corrosion reaction layer is formed between the ceramic layer and the CMAS layer. Through EDS energy spectrum scanning, this corrosion reaction layer is composed of dense Ca2Ta2O7. In the example samples, the CMAS element only exists in the corrosion reaction layer and the CMAS residual layer, preventing CMAS from further penetrating into the ceramic layer. The statistics of the depths of the corrosion layers or corrosion reaction layers of the example and comparative example samples are shown in Table 1. Combining the charts, it can be seen that the corrosion depths and corrosion rates of the samples in Examples 1 - 4 are lower than those in Examples 1 - 4. The example samples show excellent anti-CMAS corrosion performance, and during the entire corrosion process, CMAS does not penetrate into the ceramic layer.

[0044] Table 1 Statistics of the depths of the corrosion layers or corrosion reaction layers of the samples

[0045] III. Hardness Test Grind and polish the ceramic blocks obtained in Examples 1 - 4 and Comparative Examples 1 - 3, and use a micro-Vickers hardness tester to apply a load of 9.8 N to obtain the hardness value. Each sample is measured 10 times, the maximum and minimum values are removed, and the average value of the remaining values is used as the final hardness value. The results are shown in Table 2.

[0046] Table 2 Average Hardness Statistics

[0047] As can be seen from Table 2, the hardness of Examples 1 - 4 is higher than that of Comparative Examples 2 - 3, indicating that the method provided by the invention can improve the hardness of rare earth niobium tantalate

[0048] IV. Fracture Toughness Test The ceramic blocks obtained from Examples 1 - 4 and Comparative Examples 1 - 3 were polished, and the fracture toughness of niobium tantalate ceramics was calculated by the indentation method. Taking the ceramic blocks prepared from 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 each sample was tested 10 times; then, half of the diagonal length (a) of the indentation and the half crack length (c) measured from the middle of the indentation to the crack tip were obtained in the scanning electron microscope image; using the formula: ; to calculate the fracture toughness, and the average value of 10 times was taken for each sample. The calculation results are shown in Table 3

[0049] Table 3 Average Fracture Toughness Test Results

[0050] As can be seen from Table 3, the toughness of Examples 1 - 4 is higher than that of Comparative Examples 2 - 3, indicating that the method provided by the invention can improve the toughness of rare earth niobium tantalate

[0051] V. Young's Modulus Test The ceramic blocks obtained from Examples 1 - 4 and Comparative Examples 1 - 3 were polished, and the Young's modulus of the ceramics was tested by nanoindentation. The test parameters were an external load of 50 mN, a holding time of 10 s, and a Berkovich 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. The specific Young's modulus is shown in Table 4

[0052] Table 4 Young's Modulus Test Results

[0053] As can be seen from Table 4, it can be seen from Examples 1 - 4 that with the addition of tantalum element, its Young's modulus is improved. The Young's modulus of the products of Examples 2 - 4 is better than that of Example 1 and Comparative Examples 2 - 3

[0054] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope 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, \(0\leq x\leq1\), \(0\leq y\leq1\), and \(x + y = 1\), and the relative density is \(\geq95\%\).

2. The preparation method of the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 1, characterized in that, It includes the following steps: S1. Mix the pretreated oxide powder and dispersant, and ball mill to obtain slurry A; the oxide powder includes Gd₂O₃ powder, Dy₂O₃ powder, Er₂O₃ powder, Yb₂O₃ powder, Y₂O₃ powder, Nb₂O₅ powder and Ta₂O₅ powder; S2. Subject slurry A to drying, grinding and sieving in sequence, then place it in an SPS sintering mold for sintering, and cool to room temperature to obtain a ceramic block; S3. Anneal the ceramic block at a temperature of 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 preparation method of the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, wherein, In step S1, during pretreatment, the oxide powder is calcined at a temperature of 800 - 1000 °C for 2 - 3 h.

4. The preparation method of the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that, In step S1, the particle size of the oxide powder is 1 - 3 μm, and the purity is \(\geq99.99\%\).

5. The preparation method of the 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 preparation method of the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, wherein, In step S1, ball mill at 300 - 400 rpm for 12 - 48 h.

7. The preparation method of the high-entropy ceramic material with high fracture toughness and resistance to CMAS corrosion according to claim 2, characterized in that, In step S2, dry at a temperature of 70 - 90 °C for 12 - 24 h, grind for 5 - 7 min, and sieve through a 300 - 500 mesh sieve.

8. The preparation method of the 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 sinter at a temperature of 1400 - 1600 °C for 15 - 20 min.

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

10. Application 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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