High-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion and preparation method thereof

Abstract

The application discloses a high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion and a preparation method thereof. x Ca y (SiO4)6O n , wherein rare earth elements Re are selected from any 3-5 kinds of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and the stoichiometric ratio x:y:n is selected from any one of combinations 6:4:1, 7:3:1.5, 8:2:2, 25 / 3:1.5:2, 26 / 3:1:2, 28 / 3:0:2, 10:0:3. The preparation method comprises the steps of preparing a mixed powder, synthesizing a high-entropy rare earth apatite ceramic powder, preparing a green body and sintering the green body. The high-entropy rare earth apatite ceramic material can rapidly reach chemical equilibrium with CMAS, has excellent high-temperature CMAS corrosion resistance, and the preparation method has the advantages of low equipment requirement, simple and controllable process, low industrialization cost and the like, and has a very wide application prospect in the field of thermal barrier coating materials.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-entropy ceramic materials, and particularly relates to a high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion and a preparation method thereof. BACKGROUND

[0002] The improvement of the working efficiency of an aero-engine requires the increase of the pre-turbine air inlet temperature of the engine, but it will also bring the problem of high-temperature CMAS corrosion. High-temperature CMAS corrosion refers to the damage of a thermal barrier coating by CaO, MgO, Al2O3 and SiO2 (CMAS for short) at high temperature, and is one of the main problems faced by the hot end components of an aero-engine. The high-temperature CMAS melt will quickly infiltrate through the pores of the thermal barrier coating, react with the coating material, destroy the structure of the coating, cause the failure of the coating, and eventually lead to catastrophic results such as the melting of the blade. The commonly used yttrium stabilized zirconia ceramic material (YSZ) performs poorly under CMAS corrosion. At high temperature, the stable element yttrium (Y) of YSZ precipitates into the CMAS melt, and the loss of the yttrium element will cause the phase change of the material from tetragonal phase to monoclinic phase, eventually leading to the failure of the material structure, so that the material cannot serve for a long time in a high-temperature CMAS environment.

[0003] In the prior art, the development of many protective materials follows the “sacrificial protection” mechanism, that is, after the coating is dissolved, a continuous and dense inert layer is formed, which blocks the further corrosion and infiltration of CMAS. Calcium-oxygen rare earth apatite is a common stable product after the reaction of a ceramic protective material doped with rare earth and CMAS, and thus directly synthesizing calcium-oxygen rare earth apatite as a protective coating material is expected to quickly reach chemical equilibrium with CMAS and block the corrosion of CMAS. Calcium-oxygen rare earth apatite has multiple configurations, and its chemical formula is characterized by Re x Ca y (SiO4)6O n (wherein Re represents a rare earth element), and the synthesis of high-entropy apatite from multiple rare earth elements has a wide composition space. The high-entropy effect of thermodynamics, the lattice distortion effect of structure, the delayed diffusion effect of kinetics, and the “cocktail” effect of performance brought by high-entropy are expected to develop new ceramic materials with excellent high-temperature CMAS corrosion resistance. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion and a preparation method thereof.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0006] The first aspect of the present application provides a high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion, and the chemical formula of the composition components is Rex Ca y (SiO4)6O n wherein the rare earth element Re is selected from any 3-5 kinds of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and the stoichiometric ratio x:y:n is selected from any one of combinations 6:4:1, 7:3:1.5, 8:2:2, 25 / 3:1.5:2, 26 / 3:1:2, 28 / 3:0:2, 10:0:3.

[0007] Preferably, each element in Re is in an equimolar ratio.

[0008] The second aspect of the present application provides a preparation method of the high-entropy rare earth apatite ceramic material against high-temperature CMAS corrosion as described above, comprising the following steps:

[0009] S1, according to Re x Ca y (SiO4)6O n stoichiometric ratio of Re corresponding rare earth oxide powder, SiO2 powder and CaO powder are weighed and mixed and ball milled to obtain a mixed powder;

[0010] S2, the mixed powder is calcined to obtain a synthesized high-entropy rare earth apatite ceramic powder;

[0011] S3, the high-entropy rare earth apatite ceramic powder is further ball milled and then pressed to form a green body;

[0012] S4, the green body is sintered to obtain the high-entropy rare earth apatite ceramic material against high-temperature CMAS corrosion.

[0013] Preferably, in the step S1, the particle size of the rare earth oxide powder is 1-3 μm, and the purity is ≥99.9%; the particle size of the SiO2 powder and the CaO powder is 100-200 nm, and the purity is ≥99.9%.

[0014] Preferably, the ball milling is wet ball milling, and the process parameters are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder, ZrO2 balls and anhydrous ethanol is 1:5-10:1-3, and the ball milling time is 24-36 h.

[0015] Preferably, in the step S2, the specific operation of calcination is as follows: first, control the heating rate to be 3-10℃ / min to heat from room temperature to 1200-1400℃, then keep the temperature for 20-24 h, and finally cool to room temperature with the furnace.

[0016] Preferably, the specific operation of the pressing forming in step S3 is as follows: firstly, the powder is placed in a tablet press for pre-pressing, the forming pressure is 10-30 MPa, and the pressure holding time is 2-3 min; and then the powder is placed in a cold isostatic press for forming, the forming pressure is 100-300 MPa, and the pressure holding time is 3-5 min.

[0017] Preferably, the specific operation of the sintering in step S4 is as follows: firstly, the temperature is raised from room temperature to 1100-1200℃ at a rate of 5-10℃ / min, then the temperature is continuously raised to 1550-1650℃ at a rate of 3-8℃ / min, the temperature is kept for 10-25 h, and finally the temperature is cooled to room temperature.

[0018] The third aspect of the present application provides an anti-high-temperature-CMAS-corrosion high-entropy rare earth apatite ceramic material prepared by the preparation method.

[0019] The fourth aspect of the present application provides an application of the anti-high-temperature-CMAS-corrosion high-entropy rare earth apatite ceramic material in a thermal barrier coating.

[0020] The present application has the following advantages:

[0021] Calcium-oxygen-rare earth apatite is a stable product commonly formed when a ceramic protective material doped with rare earth reacts with CMAS, and the present application directly synthesizes calcium-oxygen-rare earth apatite as a protective coating material by selecting multiple rare earth elements, which can quickly reach chemical equilibrium with CMAS at high temperatures and block the further corrosion of CMAS. The high-entropy rare earth apatite ceramic material of the present application has excellent anti-high-temperature-CMAS-corrosion performance, and the corrosion depth range is 6.34-27.94 μm and the corrosion rate is 0.26-1.16 μm / h after 24 h of CMAS corrosion at 1300℃, which is much better than that of YSZ ceramic material. At the same time, the preparation method has the advantages of low equipment requirement, simple and controllable process, and low industrialization cost, and has a very broad application prospect in the field of thermal barrier coating materials. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 XRD pattern of the anti-high-temperature-CMAS-corrosion high-entropy rare earth apatite ceramic material of Example 1-4;

[0023] Figure 2 SEM pattern of the anti-high-temperature-CMAS-corrosion high-entropy rare earth apatite ceramic material of Example 1;

[0024] Figure 3BSE images of the corrosion sections of the high-entropy rare earth apatite ceramic materials of Examples 1-4 and the 8YSZ ceramic material of Comparative Example 1 after CMAS corrosion at 1300℃ for 24h. DETAILED DESCRIPTION

[0025] In order to make the objects, technical solutions of the present application clearer and more complete, the following further describes the present application in combination with the embodiments. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Any modification or equivalent replacement made by those skilled in the art based on the technical solutions of the present application without departing from the spirit and scope of the present application shall fall within the scope of the present application.

[0026] The embodiment of the present application provides a high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion, and the chemical formula is Re x Ca y (SiO4)6O n wherein the rare earth element Re is selected from any 3-5 kinds of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and the stoichiometric ratio x:y:n is selected from any one of combinations 6:4:1, 7:3:1.5, 8:2:2, 25 / 3:1.5:2, 26 / 3:1:2, 28 / 3:0:2, 10:0:3. Preferably, each element in Re is in an equimolar ratio or a near equimolar ratio.

[0027] Further, the embodiment of the present application provides a preparation method of the high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion, and the preparation method comprises the following steps.

[0028] S1, according to the stoichiometric ratio of Re x Ca y (SiO4)6O n , the rare earth oxide powder corresponding to Re, the SiO2 powder and the CaO powder are weighed and mixed and ball milled to obtain a mixed powder.

[0029] Specifically, the rare earth oxide includes La2O3, CeO2, Pr6O 11Nd2O3, Pm2O3, Sm2O3, Eu2O3, Gd2O3, Tb4O7, Dy2O3, Ho2O3, Er2O3, Tm2O3, Yb2O3, Lu2O3, Y2O3. In the embodiment of the present application, the particle size of the rare earth oxide powder used in the synthesis is 1-3 μm, and the purity is ≥99.9%; the particle size of the SiO2 powder and the CaO powder is 100-200 nm, and the purity is ≥99.9%. It is found that a too large particle size of the powder material leads to insufficient purity and a too large particle size of the final ceramic product, and results in a decrease in the CMAS corrosion resistance.

[0030] In the embodiment of the present application, the ball milling is preferably wet ball milling, the medium of the wet ball milling is preferably anhydrous ethanol, and the grinding ball is preferably a zirconium oxide (ZrO2) ball. The weight ratio of the powder, the ZrO2 ball and the anhydrous ethanol in the ball milling is preferably 1:5-10:1-3, and more preferably 1:5:2. The ball milling time is preferably 24-36 h, and the ball miller is preferably a planetary ball mill. Further, the embodiment of the present application preferably performs drying on the ball milling slurry after the wet ball milling, to obtain a mixed powder. The drying temperature is preferably 60-70℃, and the drying time is preferably 5 h, so as to remove the anhydrous ethanol in the wet ball milling slurry through drying.

[0031] S2, calcining the mixed powder to obtain the synthesized high-entropy rare earth apatite ceramic powder.

[0032] Specifically, after obtaining the mixed powder through step S1, the mixed powder is subjected to calcining treatment. Preferably, the calcining temperature is 1200-1400℃, the holding time is 20-24 h, and the temperature rising rate from room temperature to the calcining temperature is 3-10℃ / min; more preferably, the calcining temperature is 1400℃, the holding time is 20 h, and the temperature rising rate is 10℃ / min. After the calcining is completed, the powder is cooled to room temperature with the furnace. Through the calcining, the mixed powder is subjected to solid phase reaction, and the high-entropy rare earth apatite ceramic powder is synthesized.

[0033] S3, further ball milling the high-entropy rare earth apatite ceramic powder, and then performing press forming, to obtain a green body.

[0034] Specifically, the synthesized high-entropy rare earth apatite ceramic powder is further subjected to ball milling treatment to obtain more uniform and fine powder particles for pressing into a green body. The ball milling treatment in this step is preferably wet ball milling, and the wet ball milling is followed by drying treatment. The process of wet ball milling and drying treatment is step S1, which will not be described here. Further, the fine high-entropy rare earth apatite ceramic particle powder after ball milling and drying is placed in a tablet press for pre-pressing, and the forming pressure is preferably 10 MPa to 30 MPa, and the pressure holding time is preferably 2 min to 3 min; more preferably, the forming pressure is 10 MPa, and the pressure holding time is 3 min. Then, it is placed in a cold isostatic pressing machine for forming, and the forming pressure is preferably 100 MPa to 300 MPa, and the pressure holding time is preferably 3 min to 5 min; more preferably, the forming pressure is 270 MPa, and the pressure holding time is 3 min. A high-entropy rare earth apatite ceramic green body is obtained.

[0035] S4, sintering the green body to obtain the high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion.

[0036] Specifically, the pre-formed ceramic green body is subjected to sintering treatment to obtain a densified high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion. In the embodiments of the present application, the sintering temperature is preferably 1550°C to 1650°C, and the holding time is preferably 10 h to 25 h. First, the temperature is raised from room temperature to 1100°C-1200°C at a rate of 5°C / min to 10°C / min, and then the temperature is further raised from 1100°C-1200°C to the sintering temperature at a rate of 3°C / min to 8°C / min; more preferably, the sintering temperature is 1600°C, the holding time is 20 h, the temperature is first raised from room temperature to 1200°C at a rate of 10°C / min, and then the temperature is raised from 1200°C to 1600°C at a rate of 3°C / min. After sintering, the sample is cooled in the furnace, and finally a high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion is obtained.

[0037] The following examples and comparative examples are used to further illustrate the technical solutions of the present application, and the anti-CMAS corrosion performance test is carried out by the following method:

[0038] The CaO, MgO, Al2O3, SiO2 powders are mixed according to the molar percentage of CaO:MgO:Al2O3:SiO2= 60:20:10:10, and the particle size is 0.5-1.0 μm. 1.5: SiO2=33:9:13:45, which is the most widely used laboratory synthetic model CMAS corrosion in current application, is proposed by researchers from the summary of CMAS corrosion deposited on the real engine, and is widely used for testing the CMAS corrosion resistance of coating materials. The above mixture is placed in a 1300℃ box resistance furnace for constant temperature heating for 8 hours, and after cooling in the furnace, the formed glassy CMAS is ball milled to a particle size of about 30 μm powder. 10 mg of CMAS glass powder is weighed and pressed into a 3 mm diameter cylinder using a mold and placed on the surface center of the synthesized block. Then it is placed in a 1300℃ resistance furnace for a specified time, and after cooling in the furnace, the cross section of the corroded sample is made into a metallographic sample, and the corrosion area of the block by CMAS is characterized by scanning electron microscopy (SEM) with energy dispersive spectrometer (EDS).

[0039] Example 1

[0040] A high-entropy rare earth apatite ceramic material Re x Ca y (SiO4)6O n , the selected rare earth element Re is Ce, Nd, Sm, Gd, and the stoichiometric ratio x:y:n=8:2:2, and the chemical formula of the composition is (Ce 0.25 Nd 0.25 Sm 0.25 Gd 0.25 )8Ca2(SiO4)6O2.

[0041] The preparation method of the above high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion is as follows:

[0042] 1) According to the molar ratio of CeO2: Nd2O3: Sm2O3: Gd2O3: CaO: SiO2=2:1:1:1:2:6, 1.85 g of CeO2 powder, 1.80 g of Nd2O3 powder, 1.87 g of Sm2O3 powder, 1.94 g of Gd2O3 powder, 0.6 g of CaO powder and 1.93 g of SiO2 powder are weighed. The above powder raw materials are added to a planetary ball mill for wet ball milling. The process parameters of wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of powder raw materials, ZrO2 balls and anhydrous ethanol is 1:5:2, the ball milling time is 24 h, and the mixed powder slurry is obtained. The mixed powder slurry is placed in an oven for drying at 60℃ for 5 h to obtain the mixed powder.

[0043] 2) The mixed powder is loaded into a crucible and placed in a muffle furnace, the temperature rising rate is controlled at 10℃ / min from room temperature to 1400℃, and then kept for 20 h, and then cooled to room temperature in the furnace to obtain the synthesized high-entropy rare earth apatite ceramic powder.

[0044] 3) The high-entropy rare earth apatite ceramic powder is added to a planetary ball mill for wet ball milling. The process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the ceramic powder, ZrO2 balls and anhydrous ethanol is 1:5:2, the ball milling time is 24 h, and then the high-entropy rare earth apatite ceramic powder is dried in an oven. Then the high-entropy rare earth apatite ceramic powder is pre-pressed in a tablet press, the forming pressure is 10 MPa, and the pressure holding time is 3 min. Then the high-entropy rare earth apatite ceramic powder is formed in a cold isostatic pressing machine, the forming pressure is 270 MPa, and the pressure holding time is 3 min, to obtain a green body.

[0045] 4) The green body is placed in a muffle furnace, the temperature is raised from room temperature to 1200℃ at a rate of 10℃ / min, and then the temperature is raised from 1200℃ to 1600℃ at a rate of 3℃ / min, and then the temperature is maintained for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain a high-entropy rare earth apatite ceramic material (Ce 0.25 Nd 0.25 Sm 0.25 Gd 0.25 )8Ca2(SiO4)6O2.

[0046] Example 2

[0047] A high-entropy rare earth apatite ceramic material Re x Ca y (SiO4)6O n of the present embodiment is selected from Nd, Sm and Gd, the stoichiometric ratio x:y:n is 8:2:2, and the chemical formula of the composition is (Nd 1 / 3 Sm 1 / 3Gd 1 / 3 )8Ca2(SiO4)6O2.

[0048] 1) The oxide powders corresponding to the molar ratio are weighed, and the powder raw materials are added to a planetary ball mill for wet ball milling. The process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw materials, ZrO2 balls and anhydrous ethanol is 1:10:2, the ball milling time is 24 h, and then the mixed powder slurry is obtained. The mixed powder slurry is dried in an oven at 60℃ for 5 h, to obtain a mixed powder.

[0049] 2) The mixed powder is loaded into a crucible and placed in a muffle furnace, the temperature is raised from room temperature to 1400℃ at a rate of 10℃ / min, the temperature is maintained for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain a synthesized high-entropy rare earth apatite ceramic powder.

[0050] 3) The high-entropy rare earth apatite ceramic powder is added into a planetary ball mill for wet ball milling, and the process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the ceramic powder, ZrO2 balls and anhydrous ethanol is 1:10:2, the ball milling time is 24 h, and then the high-entropy rare earth apatite ceramic powder is dried in an oven. Then the high-entropy rare earth apatite ceramic powder is pre-pressed in a tablet press, the forming pressure is 10 MPa, and the pressure holding time is 3 min. Then the high-entropy rare earth apatite ceramic powder is formed in a cold isostatic pressing machine, the forming pressure is 270 MPa, and the pressure holding time is 3 min, to obtain a green body.

[0051] 4) The green body is placed in a muffle furnace, the temperature is raised from room temperature to 1100℃ at a rate of 10℃ / min, and then the temperature is raised from 1100℃ to 1550℃ at a rate of 3℃ / min, and then the temperature is maintained for 25 h, and then the temperature is cooled to room temperature in the furnace, to obtain a high-entropy rare earth apatite ceramic material (Nd 1 / 3 Sm 1 / 3 Gd 1 / 3 )8Ca2(SiO4)6O2.

[0052] Example 3

[0053] A high-entropy rare earth apatite ceramic material Re x Ca y (SiO4)6O n of the present embodiment is selected from Nd, Sm and Gd, the stoichiometric ratio x:y:n is 10:0:3, and the chemical formula of the composition is (Nd 1 / 3 Sm 1 / 3Gd 1 / 3 ) 10 (SiO4)6O3.

[0054] 1) The oxide powders corresponding to the molar ratio are weighed, and the powder raw materials are added into a planetary ball mill for wet ball milling, and the process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw materials, ZrO2 balls and anhydrous ethanol is 1:5:2, the ball milling time is 36 h, and then the mixed powder slurry is obtained. The mixed powder slurry is dried in an oven at 60℃ for 5 h to obtain the mixed powder.

[0055] 2) The mixed powder is placed in a crucible and then placed in a muffle furnace, the temperature is raised from room temperature to 1400℃ at a rate of 10℃ / min, the temperature is maintained for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain the synthesized high-entropy rare earth apatite ceramic powder.

[0056] 3) The high-entropy rare earth apatite ceramic powder is added to a planetary ball mill for wet ball milling. The process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the ceramic powder, ZrO2 balls and anhydrous ethanol is 1:5:2, the ball milling time is 24 h, and then the high-entropy rare earth apatite ceramic powder is dried in an oven. Then the high-entropy rare earth apatite ceramic powder is pre-pressed in a tablet press, the forming pressure is 10 MPa, and the pressure holding time is 3 min. Then the high-entropy rare earth apatite ceramic powder is formed in a cold isostatic pressing machine, the forming pressure is 300 MPa, and the pressure holding time is 3 min, to obtain a green body.

[0057] 4) The green body is placed in a muffle furnace, the temperature is raised from room temperature to 1200℃ at a rate of 10℃ / min, and then the temperature is raised from 1200℃ to 1600℃ at a rate of 5℃ / min, and then the temperature is held for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain the high-entropy rare earth apatite ceramic material (Nd 1 / 3 Sm 1 / 3 Gd 1 / 3 ) 10 (SiO4)6O3.

[0058] Example 4

[0059] The high-entropy rare earth apatite ceramic material Re x Ca y (SiO4)6O n of the present embodiment is a high-entropy rare earth apatite ceramic material (Nd 0.25 Nd 0.25 Sm 0.25 Gd 0.25 ) 28 / 3 (SiO4)6O2.

[0060] 1) The oxide powders corresponding to the molar ratio are weighed, and the powder raw materials are added to a planetary ball mill for wet ball milling. The process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw materials, ZrO2 balls and anhydrous ethanol is 1:5:3, and the ball milling time is 24 h, to obtain a mixed powder slurry. The mixed powder slurry is dried in an oven at 60℃ for 5 h, to obtain a mixed powder.

[0061] 2) The mixed powder is loaded into a crucible and placed in a muffle furnace, the temperature is raised from room temperature to 1400℃ at a rate of 10℃ / min, the temperature is held for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain the synthesized high-entropy rare earth apatite ceramic powder.

[0062] 3) The high-entropy rare earth apatite ceramic powder is added into a planetary ball mill for wet ball milling. The process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the ceramic powder, ZrO2 balls and anhydrous ethanol is 1:5:3, the ball milling time is 24 h, and then the high-entropy rare earth apatite ceramic powder is dried in an oven. Then the high-entropy rare earth apatite ceramic powder is pre-pressed in a tablet press, the forming pressure is 30 MPa, and the pressure holding time is 3 min. Then the high-entropy rare earth apatite ceramic powder is formed in a cold isostatic pressing machine, the forming pressure is 270 MPa, and the pressure holding time is 5 min, to obtain a green body.

[0063] 4) The green body is placed in a muffle furnace, the temperature is raised from room temperature to 1200℃ at a rate of 10℃ / min, and then the temperature is raised from 1200℃ to 1600℃ at a rate of 3℃ / min, and then the temperature is kept for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain the high-entropy rare earth apatite ceramic material (Ce 0.25 Nd 0.25 Sm 0.25 Gd 0.25 ) 28 / 3 (SiO4)6O2.

[0064] Example 5

[0065] The high-entropy rare earth apatite ceramic material Re x Ca y (SiO4)6O n , the rare earth element Re is La, Ce, Nd, Sm or Gd, the stoichiometric ratio x:y:n is 8:2:2, and the chemical formula of the composition is (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Gd 0.2 )8Ca2(SiO4)6O2.

[0066] 1) The oxide powders corresponding to the molar ratio are weighed, and the powder raw materials are added into a planetary ball mill for wet ball milling. The process parameters of the wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder raw materials, ZrO2 balls and anhydrous ethanol is 1:5:2, the ball milling time is 24 h, and then the mixed powder slurry is obtained. The mixed powder slurry is dried in an oven at 60℃ for 5 h, to obtain the mixed powder.

[0067] 2) The mixed powder is placed in a crucible and then placed in a muffle furnace, the temperature is raised from room temperature to 1400℃ at a rate of 10℃ / min, the temperature is kept for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain the synthesized high-entropy rare earth apatite ceramic powder.

[0068] 3) The high-entropy rare earth apatite ceramic powder is added to a planetary ball mill for wet ball milling. The process parameters for wet ball milling are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the ceramic powder, ZrO2 balls and anhydrous ethanol is 1:5:2, the ball milling time is 24 h, and then the high-entropy rare earth apatite ceramic powder is dried in an oven. Then the high-entropy rare earth apatite ceramic powder is pre-pressed in a tablet press, the forming pressure is 10 MPa, and the pressure holding time is 3 min. Then the high-entropy rare earth apatite ceramic powder is formed in a cold isostatic pressing machine, the forming pressure is 270 MPa, and the pressure holding time is 3 min, to obtain a green body;

[0069] 4) The green body is placed in a muffle furnace, the temperature is raised from room temperature to 1200℃ at a rate of 10℃ / min, and then the temperature is raised from 1200℃ to 1550℃ at a rate of 5℃ / min, and then the temperature is maintained for 20 h, and then the temperature is cooled to room temperature in the furnace, to obtain the high-entropy rare earth apatite ceramic material (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Gd 0.2 )8Ca2(SiO4)6O2.

[0070] Comparative Example 1

[0071] 8% of Y2O3 and 92% of ZrO2 powder are weighed according to the mass ratio, and the ceramic 8YSZ is prepared by the preparation method described in Example 1.

[0072] Characterization and performance test

[0073] 1) The X-ray diffraction (XRD) pattern of the high-entropy rare earth apatite ceramic material prepared in the above examples is shown in Figure 1 . It can be seen from Figure 1 that the high-entropy rare earth apatite ceramic materials synthesized in Examples 1-4 are uniform single-phase rare earth apatite phases, and no other impurity phases are found.

[0074] 2) The scanning electron microscope (SEM) image of the high-entropy rare earth apatite ceramic material prepared in Example 1 is shown in Figure 2 . It can be seen from Figure 2 that the high-entropy rare earth apatite ceramic material synthesized in Example 1 is dense, and there are no obvious pores and cracks on the surface.

[0075] 3) According to the above anti-CMAS corrosion performance test method, 10 mg of CMAS glass powder was weighed and pressed into a cylinder with a diameter of 3 mm using a mold, and placed at the center of the surface of the bulk ceramic material of Examples 1-4 and Comparative Example 1, and then placed in a resistance furnace at 1300°C for 24 h. After corrosion, each sample was prepared into a scanning electron microscope sample, and the thickness of the CMAS corrosion reaction layer on the surface of the material of Examples 1-4 and Comparative Example 1 was observed using a scanning electron microscope, and the results are shown in the backscattered scanning electron microscope (BSE) images of FIGS. 6-9. Figure 3 As can be seen from the figures, CMAS and high-entropy rare earth apatite reach chemical equilibrium, the corrosion depth of the material of Examples 1-4 is in the range of 6.34 μm-27.94 μm, and the corrosion rate is 0.26 μm / h-1.16 μm / h, while the corrosion depth of the material of Comparative Example 1 is 77.66 μm, and the corrosion rate is 3.23 μm / h, indicating that the high-entropy rare earth apatite ceramic material prepared by Examples 1-4 has better anti-CMAS corrosion performance than the existing commonly used coating material 8YSZ.

[0076] The above examples are the preferred embodiments of the present application, but the embodiments of the present application are not limited by the above examples, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application are equivalent replacement methods and are included in the protection scope of the present application.

Claims

1. A high-entropy rare-earth apatite ceramic material resistant to high-temperature CMAS corrosion, characterized in that, The chemical formula of the constituent is (Ce 0.25 Nd 0.25 Sm 0.25 Gd 0.25 )8Ca2(SiO4)6O2, (Nd 1 / 3 Sm 1 / 3 Gd 1 / 3 )8Ca2(SiO4)6O2, (Nd 1 / 3 Sm 1 / 3 Gd 1 / 3 ) 10 (SiO4)6O3, (Ce 0.25 Nd 0.25 Sm 0.25 Gd 0.25 ) 28 / 3 (SiO4)6O2 or (La 0.2 Ce 0.2 Nd 0.2 Sm 0.2 Gd 0.2 )8Ca2(SiO4)6O2.

2. A method for preparing the high-entropy rare-earth apatite ceramic material resistant to CMAS corrosion at high temperature according to claim 1, characterized in that, It comprises the following steps: S1, according to the chemical formula described in claim 1, the corresponding rare earth oxide powder, SiO2 powder, CaO powder is weighed and mixed and ball milled to obtain a mixed powder; S2, the mixed powder is calcined to obtain a synthesized high-entropy rare earth apatite ceramic powder; S3, the high-entropy rare earth apatite ceramic powder is further ball milled and then pressed to form a green body; S4, the green body is sintered to obtain the high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion.

3. The preparation method according to claim 2, characterized in that, In the step S1, the particle size of the rare earth oxide powder is 1-3 μm, and the purity is ≥99.9%; the particle size of the SiO2 powder and the CaO powder is 100-200 nm, and the purity is ≥99.9%.

4. The preparation method according to claim 2, characterized in that, The ball milling is wet ball milling, and the process parameters are as follows: the ball milling medium is anhydrous ethanol, the weight ratio of the powder, ZrO2 balls and anhydrous ethanol is 1:5-10:1-3, and the ball milling time is 24-36 h.

5. The preparation method according to claim 2, characterized in that, In the step S2, the specific operation of calcination is as follows: first, control the heating rate to be 3-10 ℃ / min to heat from room temperature to 1200-1400 ℃, then keep the temperature for 20-24 h, and finally cool to room temperature with the furnace.

6. The preparation method according to claim 2, characterized in that, In the step S3, the specific operation of pressing is as follows: first, the powder is placed in a tablet press for pre-pressing, the forming pressure is 10-30 MPa, and the pressure holding time is 2-3 min; then, it is placed in a cold isostatic pressing machine for forming, the forming pressure is 100-300 MPa, and the pressure holding time is 3-5 min.

7. The preparation method according to claim 2, characterized in that, In the step S4, the specific operation of sintering is as follows: first, control the heating rate to be 5-10 ℃ / min to heat from room temperature to 1100-1200 ℃, then control the heating rate to be 3-8 ℃ / min to continue heating to 1550-1650 ℃, keep the temperature for 10-25 h, and finally cool to room temperature with the furnace.

8. The application of the high-entropy rare earth apatite ceramic material resistant to high-temperature CMAS corrosion according to claim 1 in a thermal barrier coating.

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