A high-entropy rare earth disilicate material and its preparation method and application

Abstract

The present invention provides a high entropy rare earth disilicate material and its preparation method and application, which relates to the technical field of environmental barrier coating materials. The molecular formula of the high entropy rare earth disilicate material provided by the present invention is (xRE 1 / X )2Si2O7; RE includes at least four of Lu, Yb, Sc, Er, Y, Ho, Dy, and Tb; and x ranges from 4 to 8. The high-entropy rare earth disilicate material provided by the present invention is free of impurities, exhibits excellent high-temperature chemical stability, and exhibits strong resistance to CMAS corrosion. The high-entropy rare earth disilicate material of the present invention has a low thermal conductivity coefficient and strong resistance to CMAS corrosion at 1300°C, meeting the requirements for use as an environmental barrier coating.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental barrier coating materials, and in particular to a high-entropy rare earth disilicate material, a preparation method thereof, and applications thereof. Background Art

[0002] With the development of the aerospace industry, coupled with the increasing temperatures and combustion pressures in aircraft engine combustion chambers, aircraft engines are facing increasingly demanding operating environments. For decades, the industry has focused on developing engines with superior performance, such as high flow rate ratios, high thrust-to-weight ratios, and high turbine inlet temperatures. Among these characteristics, high turbine inlet temperatures are crucial for achieving both high thrust-to-weight ratios and high thermal efficiency. For example, when the engine's combustion chamber temperature is 1650°C, the thrust-to-weight ratio is 8. To achieve a higher thrust-to-weight ratio, the combustion chamber temperature must reach 1850°C or higher. Nickel-based superalloys, widely used as materials for hot-end components, can withstand temperatures as high as 1075°C, approaching their inherent limits. This makes it difficult for these alloys to meet the rapid development and urgent demands of advanced aircraft engines.

[0003] SiC-based ceramic composites (SiC-CMCs) have gradually become the hot end components of aircraft engines due to their light weight, high strength and high temperature resistance. However, in practical applications, SiC-CMCs are subject to high-temperature water vapor corrosion and CMAS corrosion, which in turn reduces structural stability and service life. Therefore, a layer of environmental barrier coatings (EBCs) is usually prepared on their surface to isolate water vapor and CMAS molten salts. Rare earth disilicates have excellent oxidation resistance, resistance to high-temperature water vapor corrosion, and a thermal expansion coefficient that matches that of SiC-CMCs. They are candidate materials for the new generation of EBCs. However, rare earth disilicates have problems such as poor high-temperature structural stability and weak resistance to molten CMAS corrosion that need to be urgently addressed. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-entropy rare earth disilicate material and its preparation method and application. The high-entropy rare earth disilicate material provided by the present invention has good high-temperature chemical stability and strong resistance to CMAS corrosion.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a high entropy rare earth disilicate material, the molecular formula of which is (xRE 1 / X )2Si2O7; RE includes four or more of Lu, Yb, Sc, Er, Y, Ho, Dy and Tb; the range of x is 4 to 8.

[0007] Preferably, the elements in the RE are in an equimolar ratio or a nearly equimolar ratio.

[0008] Preferably, the high entropy rare earth disilicate material is a β monoclinic phase.

[0009] The present invention provides a method for preparing the high-entropy rare earth disilicate material described in the above technical solution, comprising the following steps:

[0010] (1) SiO2 and RE2O3 are mixed according to (xRE 1 / X )2Si2O7 in a stoichiometric ratio to obtain a mixed powder;

[0011] (2) The mixed powder is subjected to a first sintering and ball milling to obtain (xRE 1 / X )2Si2O7 ceramic powder;

[0012] (3) The (xRE 1 / X )2Si2O7 ceramic powder is pressed to obtain (xRE 1 / X )2Si2O7 ceramic block;

[0013] (4) the (xRE 1 / X )2Si2O7 ceramic block is subjected to a second sintering to obtain the high entropy rare earth disilicate material.

[0014] Preferably, the mixing in step (1) is wet ball milling mixing.

[0015] Preferably, the grinding balls used in the wet ball milling include large-sized zirconia balls, medium-sized zirconia balls and small-sized zirconia balls; the size of the large-sized zirconia balls is Φ7-9 mm; the size of the medium-sized zirconia balls is Φ4-6 mm; the size of the small-sized zirconia balls is Φ2-4 mm; the mass ratio of the large-sized zirconia balls, medium-sized zirconia balls and small-sized zirconia balls is 1:1-3:1;

[0016] The rotation speed of the wet ball milling is 350-450 rpm, and the ball milling time is 10-12 hours.

[0017] Preferably, in step (2), the temperature of the first sintering is 1400-1600° C., and the holding time is 3-5 hours; the heating rate from room temperature to the first sintering temperature is 3-6° C. / min.

[0018] Preferably, the pressing pressure in step (3) is 3 to 6 MPa, and the holding time is 3 to 6 minutes.

[0019] Preferably, in step (4), the temperature of the second sintering is 1500-1700° C., and the holding time is 5-15 hours; the heating rate from room temperature to the second sintering temperature is 4-8° C. / min.

[0020] The present invention provides the use of the high-entropy rare earth disilicate material described in the above technical solution or the high-entropy rare earth disilicate material prepared by the preparation method described in the above technical solution in an environmental barrier coating.

[0021] The present invention provides a high-entropy rare earth disilicate material. In the present invention, the single-component rare earth disilicates of Lu, Yb, and Sc are all β-phase-stabilized ceramics. Therefore, due to the entropy stabilization effect and synergistic effect of the high-entropy ceramic, the high-entropy ceramic formed after adding other rare earth elements is pure phase and has good chemical stability. In the present invention, after multiple elements are dissolved into a high-entropy ceramic, a large lattice distortion is generated. On the one hand, the increase in lattice distortion enhances phonon scattering, thereby reducing the thermal conductivity of the material. On the other hand, the increase in lattice distortion complicates the channels for atomic diffusion, and due to the hysteresis diffusion effect, the corrosion resistance of CMAS is enhanced. The high-entropy rare earth disilicate material provided by the present invention is free of impurities, has good high-temperature chemical stability, and has strong resistance to CMAS corrosion. The high-entropy rare earth disilicate material described in the present invention has a low thermal conductivity coefficient and strong resistance to CMAS corrosion at 1300°C, meeting the requirements for use as an environmental barrier coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the XRD spectrum of the high entropy rare earth disilicate material prepared in Example 1;

[0023] Figure 2 This is the SEM image of the high entropy rare earth disilicate material prepared in Example 1;

[0024] Figure 3 This is the thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 1;

[0025] Figure 4 This is a cross-sectional SEM image of the high-entropy rare earth disilicate material prepared in Example 1 after being corroded at 1300°C for 48 hours;

[0026] Figure 5 This is the XRD spectrum of the high entropy rare earth disilicate material prepared in Example 2;

[0027] Figure 6 This is the SEM image of the high entropy rare earth disilicate material prepared in Example 2;

[0028] Figure 7 This is the thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 2;

[0029] Figure 8 This is a cross-sectional SEM image of the high-entropy rare earth disilicate material prepared in Example 2 after being corroded at 1300°C for 48 hours;

[0030] Figure 9 This is the XRD spectrum of the high entropy rare earth disilicate material prepared in Example 3;

[0031] Figure 10 This is the SEM image of the high entropy rare earth disilicate material prepared in Example 3;

[0032] Figure 11 This is the thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 3;

[0033] Figure 12 This is a cross-sectional SEM image of the high-entropy rare earth disilicate material prepared in Example 3 after being corroded at 1300°C for 48 hours;

[0034] Figure 13 This is the XRD spectrum of the high entropy rare earth disilicate material prepared in Example 4;

[0035] Figure 14 This is the SEM image of the high-entropy rare earth disilicate material prepared in Example 4;

[0036] Figure 15 This is the thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 4;

[0037] Figure 16 This is a cross-sectional SEM image of the high-entropy rare earth disilicate material prepared in Example 4 after being corroded at 1300°C for 48 hours. DETAILED DESCRIPTION

[0038] The present invention provides a high entropy rare earth disilicate material, the molecular formula of which is (xRE 1 / X )2Si2O7; RE includes four or more of Lu, Yb, Sc, Er, Y, Ho, Dy and Tb; the range of x is 4 to 8.

[0039] In the present invention, the elements in the RE are preferably in an equal molar ratio or a nearly equal molar ratio. In the present invention, x represents the number of elements in the RE.

[0040] In the present invention, the high entropy rare earth disilicate material is preferably a β monoclinic phase.

[0041] In the present invention, the RE preferably includes at least Lu, Yb and Sc. In a specific embodiment of the present invention, the high entropy rare earth disilicate material includes (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7、(Lu 1 / 7 Yb 1 / 7 Sc 1 / 7Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7、(Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 or (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7.

[0042] The present invention provides a method for preparing the high-entropy rare earth disilicate material described in the above technical solution, comprising the following steps:

[0043] (1) SiO2 and RE2O3 are mixed according to (xRE 1 / X )2Si2O7 in a stoichiometric ratio to obtain a mixed powder;

[0044] (2) The mixed powder is subjected to a first sintering and ball milling to obtain (xRE 1 / X )2Si2O7 ceramic powder;

[0045] (3) The (xRE 1 / X )2Si2O7 ceramic powder is pressed to obtain (xRE 1 / X )2Si2O7 ceramic block;

[0046] (4) the (xRE 1 / X )2Si2O7 ceramic block is subjected to a second sintering to obtain the high entropy rare earth disilicate material.

[0047] The present invention combines SiO2 and RE2O3 according to (xRE 1 / X)2Si2O7 are mixed in a stoichiometric ratio to obtain a mixed powder. In the present invention, the RE2O3 includes four or more of Lu2O3, Yb2O3, Sc2O3, Er2O3, Y2O3, Ho2O3, Dy2O3 and Tb2O3. In the present invention, the particle size of the RE2O3 is preferably 500nm. In the present invention, the RE2O3 is preferably subjected to a high-temperature de-crystallization water treatment before use; the high-temperature de-crystallization water treatment preferably includes heating to 1000℃ at a rate of 2-6℃ / min and keeping warm for 3h, followed by cooling with the furnace. In the present invention, the high-temperature de-crystallization water treatment is preferably carried out in a corundum crucible. The present invention first performs a high-temperature de-crystallization water treatment on RE2O3, which can ensure the accuracy of weighing.

[0048] In the present invention, the mixing is preferably wet ball milling. The medium for wet ball milling is preferably anhydrous ethanol. The mass ratio of the total mass of SiO2 and RE2O3 to anhydrous ethanol during wet ball milling is preferably 1:2. The grinding balls used in the wet ball milling preferably include large-sized zirconia balls, medium-sized zirconia balls, and small-sized zirconia balls. The large-sized zirconia balls are preferably 7-9 mm in diameter, more preferably 8 mm in diameter; the medium-sized zirconia balls are preferably 4-6 mm in diameter, more preferably 5 mm in diameter; and the small-sized zirconia balls are preferably 2-4 mm in diameter, more preferably 3 mm in diameter. The mass ratio of the large-sized zirconia balls, medium-sized zirconia balls, and small-sized zirconia balls is preferably 1:1-3:1, more preferably 1:2:1. The mass ratio of the balls to the materials during wet ball milling is preferably 3-5:1, more preferably 4:1. In the present invention, the rotation speed of the wet ball milling is preferably 350 to 450 rpm, more preferably 400 rpm; and the ball milling time is preferably 10 to 12 h.

[0049] In the present invention, after the wet ball milling, the resulting ball milled slurry is preferably dried to obtain a mixed powder. In the present invention, the drying temperature is preferably 70°C; the drying time is preferably 12 to 24 hours, more preferably 20 hours. The present invention removes the wet ball milling medium by drying.

[0050] After obtaining the mixed powder, the present invention performs a first sintering on the mixed powder and ball milling to obtain (xRE 1 / X )2Si2O7 ceramic powder. In the present invention, the mixed powder is preferably firstly ground until there are no agglomerates, then passed through a 120 mesh sieve, and then subjected to a first sintering.

[0051] In the present invention, the temperature of the first sintering is preferably 1400-1600°C, more preferably 1500°C; the holding time is preferably 3-5h, more preferably 4h; the heating rate from room temperature to the temperature of the first sintering is preferably 3-6°C / min, more preferably 5°C / min. In the present invention, the atmosphere of the first sintering is preferably air atmosphere. The present invention causes the mixed powder to undergo solid phase reaction through the first sintering to obtain (xRE 1 / X )2Si2O7. In the present invention, the first sintering is preferably followed by cooling to room temperature in the furnace.

[0052] In the present invention, the ball milling is preferably performed in a planetary ball mill. In the present invention, the ball milling is preferably wet ball milling. In the present invention, the medium for wet ball milling is preferably anhydrous ethanol. The mass ratio of the sintered powder to anhydrous ethanol during wet ball milling is preferably 1:2. In the present invention, the grinding balls used in the wet ball milling preferably include large-sized zirconia balls, medium-sized zirconia balls, and small-sized zirconia balls. The large-sized zirconia balls are preferably 7-9 mm in diameter, more preferably 8 mm in diameter; the medium-sized zirconia balls are preferably 4-6 mm in diameter, more preferably 5 mm in diameter; and the small-sized zirconia balls are preferably 2-4 mm in diameter, more preferably 3 mm in diameter. The mass ratio of the large-sized zirconia balls, medium-sized zirconia balls, and small-sized zirconia balls is preferably 1:1-3:1, more preferably 1:2:1. In the present invention, the mass ratio of the balls to materials during wet ball milling is preferably 3-5:1, more preferably 4:1. In the present invention, the wet ball milling rotation speed is preferably 350-450 rpm, more preferably 400 rpm, and the ball milling time is preferably 5-10 hours. In the present invention, after the wet ball milling, the resulting ball milled slurry is preferably dried to obtain a mixed powder. In the present invention, the drying temperature is preferably 60-80°C, more preferably 70°C, and the drying time is preferably 6-12 hours. Drying is performed to remove the wet ball milling medium.

[0053] Get (xRE 1 / X )2Si2O7 ceramic powder, the present invention (xRE 1 / X )2Si2O7 ceramic powder is pressed to obtain (xRE 1 / X )2Si2O7 ceramic block. In the present invention, the pressing pressure is preferably 3-6 MPa, more preferably 5 MPa; the holding time is preferably 3-6 minutes, more preferably 5 minutes. In the present invention, the pressing temperature is preferably room temperature. In the present invention, the pressing is preferably performed using a desktop powder tablet press.

[0054] Get (xRE 1 / X )2Si2O7 ceramic block, the present invention will (xRE1 / X )2Si2O7 ceramic block is subjected to a second sintering to obtain the high entropy rare earth disilicate material. In the present invention, the temperature of the second sintering is preferably 1500-1700°C, more preferably 1600°C, and the holding time is preferably 5-15h, more preferably 10h; the heating rate from room temperature to the temperature of the second sintering is preferably 4-8°C / min, more preferably 5°C / min. In the present invention, the atmosphere of the second sintering is preferably an air atmosphere. The present invention sinters the preformed ceramic powder into a dense ceramic block through the second sintering.

[0055] The present invention provides the use of the high-entropy rare earth disilicate material described in the above technical solution or the high-entropy rare earth disilicate material prepared by the preparation method described in the above technical solution in an environmental barrier coating.

[0056] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0057] Example 1

[0058] (1) The raw material powder of RE2O3 (Lu2O3, Yb2O3, Sc2O3, Er2O3, Y2O3, Ho2O3, Dy2O3 and Tb2O3) was heat treated at 1000℃ for 3h and then cooled to 50℃. 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 (molar ratio) RE2O3 and SiO2 were placed in a ball mill and ball-milled using anhydrous ethanol as a medium to obtain a slurry; wherein the diameters of the zirconia ball milling balls were Φ8mm, Φ5mm, and Φ3mm, with a mass ratio of 1:2:1; the ball-to-material mass ratio was 4:1, the ball milling time was 12 hours, and the rotation speed was 400rpm;

[0059] (2) Pour the ball-milled slurry in (1) into a beaker and dry it in an oven at 70°C for 20 h to remove anhydrous ethanol to obtain a mixed powder;

[0060] (3) The mixed powder was placed in a mortar and ground thoroughly until there were no agglomerates, then passed through a 120-mesh sieve, placed in a corundum crucible, and placed in a muffle furnace. The temperature was raised to 1500°C at a heating rate of 5°C / min in an air atmosphere, and the temperature was kept at that temperature for 4 hours, and then cooled to room temperature with the furnace to obtain (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 powder;

[0061] (4) The sintered (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 powder was placed in a ball mill jar containing hard zirconia balls after being washed with deionized water. Zirconia balls of sizes of Φ8mm, Φ5mm, and Φ3mm were poured into the ball mill jar at a mass ratio of 1:2:1. Anhydrous ethanol was used as the medium, the ball-to-material mass ratio was 4:1, the rotation speed was 400rpm, and after ball milling for 10 hours, (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 ceramic powder slurry;

[0062] (5) The (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 ceramic powder slurry is dried at 70℃ for 12h;

[0063] (6) The (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8)2Si2O7 ceramic powder was pressed into a cylinder with a diameter of 12mm and pressed into (Lu 1 / 8 Yb 1 / 8Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 ceramic block;

[0064] (7) The (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 ceramic blocks were placed in a ZrO2 crucible and placed in a muffle furnace at 1600℃, a heating rate of 5℃ / min, and a holding time of 10h to prepare a high entropy rare earth disilicate material (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7.

[0065] The density of the high entropy rare earth disilicate material prepared in this example is 5.08 g / cm 3 , heat capacity is 0.52~0.64J·g -1 ·K -1 .

[0066] Example 2

[0067] (1) The raw material powder of RE2O3 (Lu2O3, Yb2O3, Sc2O3, Er2O3, Y2O3, Ho2O3 and Dy2O3) was heat treated at 1000℃ for 3h and then cooled to 50℃. 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7)2Si2O7 (molar ratio) RE2O3 and SiO2 were placed in a ball mill and ball-milled using anhydrous ethanol as a medium to obtain a slurry; wherein the diameters of the zirconia ball milling balls were Φ8mm, Φ5mm, and Φ3mm, with a mass ratio of 1:2:1; the ball-to-material mass ratio was 4:1, the ball milling time was 12 hours, and the rotation speed was 400rpm;

[0068] (2) Pour the ball-milled slurry in (1) into a beaker and dry it in an oven at 70°C for 20 h to remove anhydrous ethanol to obtain a mixed powder;

[0069] (3) The mixed powder was placed in a mortar and ground thoroughly until there were no agglomerates, then passed through a 120-mesh sieve, placed in a corundum crucible, and placed in a muffle furnace. The temperature was raised to 1500°C at a heating rate of 5°C / min in an air atmosphere, and the temperature was kept at that temperature for 4 hours, and then cooled to room temperature with the furnace to obtain (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 powder;

[0070] (4) The sintered (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 powder was placed in a ball mill jar containing hard zirconia balls after being washed with deionized water. Zirconia balls of sizes of Φ8mm, Φ5mm, and Φ3mm were poured into the ball mill jar at a mass ratio of 1:2:1. Anhydrous ethanol was used as the medium, the ball-to-material mass ratio was 4:1, the rotation speed was 400rpm, and after ball milling for 10 hours, (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 ceramic powder slurry;

[0071] (5) The (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 ceramic powder slurry is dried at 70℃ for 12h;

[0072] (6) The (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 ceramic powder was pressed into a cylinder with a diameter of 12mm and pressed into (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 ceramic block;

[0073] (7) The (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 ceramic blocks were placed in a ZrO2 crucible and placed in a muffle furnace at 1600℃, a heating rate of 5℃ / min, and a holding time of 10h to prepare a high entropy rare earth disilicate material (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7.

[0074] The density of the high entropy rare earth disilicate material prepared in this example is 5.06 g / cm 3 , heat capacity is 0.53~0.65J·g -1 ·K -1 .

[0075] Example 3

[0076] (1) The raw material powder of RE2O3 (Lu2O3, Yb2O3, Sc2O3, Er2O3, Y2O3 and Ho2O3) was heat treated at 1000℃ for 3h and then cooled to 50℃. 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6)2Si2O7 (molar ratio) RE2O3 and SiO2 were placed in a ball mill and ball-milled using anhydrous ethanol as a medium to obtain a slurry; wherein the diameters of the zirconia ball milling balls were Φ8mm, Φ5mm, and Φ3mm, with a mass ratio of 1:2:1; the ball-to-material mass ratio was 4:1, the ball milling time was 12 hours, and the rotation speed was 400rpm;

[0077] (2) Pour the ball-milled slurry in (1) into a beaker and dry it in an oven at 70°C for 20 h to remove anhydrous ethanol to obtain a mixed powder;

[0078] (3) The mixed powder was placed in a mortar and ground thoroughly until there were no agglomerates, then passed through a 120-mesh sieve, placed in a corundum crucible, and placed in a muffle furnace. The temperature was raised to 1500°C at a heating rate of 5°C / min in an air atmosphere, and the temperature was kept at that temperature for 4 hours, and then cooled to room temperature with the furnace to obtain (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 powder;

[0079] (4) The sintered (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 powder was placed in a ball mill jar containing hard zirconia balls after being washed with deionized water. Zirconia balls of sizes of Φ8mm, Φ5mm, and Φ3mm were poured into the ball mill jar at a mass ratio of 1:2:1. Anhydrous ethanol was used as the medium, the ball-to-material mass ratio was 4:1, the rotation speed was 400rpm, and after ball milling for 10 hours, (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 ceramic powder slurry;

[0080] (5) The (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 ceramic powder slurry is dried at 70℃ for 12h;

[0081] (6) The (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 ceramic powder was pressed into a cylinder with a diameter of 12mm and pressed into (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 ceramic block;

[0082] (7) The (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 ceramic blocks were placed in a ZrO2 crucible and placed in a muffle furnace at 1600℃, a heating rate of 5℃ / min, and a holding time of 10h to prepare a high entropy rare earth disilicate material (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7.

[0083] The density of the high entropy rare earth disilicate material prepared in this example is 5.10 g / cm 3 , heat capacity is 0.52~0.65J·g -1 ·K -1 .

[0084] Example 4

[0085] (1) The raw material powder of RE2O3 (Lu2O3, Yb2O3, Sc2O3, Er2O3 and Y2O3) was heat treated at 1000℃ for 3h and then cooled to 50℃. 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7 (molar ratio) RE2O3 and SiO2 were placed in a ball mill and ball-milled using anhydrous ethanol as a medium to obtain a slurry; wherein the diameters of the zirconia ball milling balls were Φ8mm, Φ5mm, and Φ3mm, with a mass ratio of 1:2:1; the ball-to-material mass ratio was 4:1, the ball milling time was 12 hours, and the rotation speed was 400rpm;

[0086] (2) Pour the ball-milled slurry in (1) into a beaker and dry it in an oven at 70°C for 20 h to remove anhydrous ethanol to obtain a mixed powder;

[0087] (3) The mixed powder was placed in a mortar and ground thoroughly until there were no agglomerates, then passed through a 120-mesh sieve, placed in a corundum crucible, and placed in a muffle furnace. The temperature was raised to 1500°C at a heating rate of 5°C / min in an air atmosphere, and the temperature was kept at that temperature for 4 hours, and then cooled to room temperature with the furnace to obtain (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7 powder;

[0088] (4) The sintered (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7 powder was placed in a ball mill jar containing hard zirconia balls after being washed with deionized water. Zirconia balls of sizes of Φ8mm, Φ5mm, and Φ3mm were poured into the ball mill jar at a mass ratio of 1:2:1. Anhydrous ethanol was used as the medium, the ball-to-material mass ratio was 4:1, the rotation speed was 400rpm, and after ball milling for 10 hours, (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7 ceramic powder slurry;

[0089] (5) The (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7 ceramic powder slurry is dried at 70℃ for 12h;

[0090] (6) The (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7 ceramic powder was pressed into a cylinder with a diameter of 12mm and pressed into (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5Y 1 / 5 )2Si2O7 ceramic block;

[0091] (7) The (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er1 / 5 Y 1 / 5 )2Si2O7 ceramic blocks were placed in a ZrO2 crucible and placed in a muffle furnace at 1600℃, a heating rate of 5℃ / min, and a holding time of 10h to prepare a high entropy rare earth disilicate material (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7.

[0092] The density of the high entropy rare earth disilicate material prepared in this example is 5.18 g / cm 3 , heat capacity is 0.55~0.68J·g -1 ·K -1 .

[0093] Test Case

[0094] (1) X-ray diffraction (XRD) test

[0095] The high entropy rare earth disilicate material prepared in Example 1 was subjected to XRD testing, and the results were as follows: Figure 1 As shown, (Lu 1 / 8Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 diffraction peaks are in good agreement with the β-Yb2Si2O7 standard card PDF#81-0792, and no other impurity peaks appear, indicating that β-(Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8Tb 1 / 8 )2Si2O7 ceramic phase.

[0096] The high entropy rare earth disilicate material prepared in Example 2 was subjected to XRD detection, and the results were as follows: Figure 5 As shown, it is shown that (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7 Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 ceramic phase.

[0097] The high entropy rare earth disilicate material prepared in Example 3 was subjected to XRD detection, and the results were as follows: Figure 9 As shown, it is shown that (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6 Er 1 / 6 Y 1 / 6 Ho 1 / 6 )2Si2O7 ceramic phase.

[0098] The high entropy rare earth disilicate material prepared in Example 4 was subjected to XRD detection, and the results were as follows: Figure 13 As shown, it is shown that (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5 Er 1 / 5 Y 1 / 5 )2Si2O7 ceramic phase.

[0099] (2) Scanning electron microscopy (SEM) observation

[0100] The high entropy rare earth disilicate material prepared in Example 1 was observed by SEM. Figure 2 As shown in the figure, the surface morphology of the material is dense, without holes and cracks, which proves that high-density (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 bulk material.

[0101] The high entropy rare earth disilicate material prepared in Example 2 was observed by SEM. Figure 6 As shown in the figure, the surface morphology of the material is dense, without holes and cracks, which proves that high-density (Lu 1 / 7 Yb 1 / 7 Sc 1 / 7Er 1 / 7 Y 1 / 7 Ho 1 / 7 Dy 1 / 7 )2Si2O7 bulk material.

[0102] The high entropy rare earth disilicate material prepared in Example 3 was observed by SEM. Figure 10 As shown in the figure, the surface morphology of the material is dense, without holes and cracks, which proves that high-density (Lu 1 / 6 Yb 1 / 6 Sc 1 / 6Er 1 / 6 Y1 / 6 Ho 1 / 6 )2Si2O7 bulk material.

[0103] The high entropy rare earth disilicate material prepared in Example 4 was observed by SEM. Figure 14 As shown in the figure, the surface morphology of the material is dense, without holes and cracks, which proves that high-density (Lu 1 / 5 Yb 1 / 5 Sc 1 / 5Er 1 / 5 Y 1 / 5 )2Si2O7 bulk material.

[0104] (3) Thermal conductivity test

[0105] The thermal diffusivity (D) of the high entropy rare earth disilicate material prepared in the embodiment was measured by laser flash method. th ), the thermal conductivity (κ) is calculated according to formula 1:

[0106] k=D th ·C p ·ρ Equation 1;

[0107] In formula 1, κ is the thermal conductivity of the high entropy rare earth disilicate material, in W·m -1 ·K -1 ;D th is the thermal diffusivity, in mm 2 / s; ρ is the density of high entropy rare earth disilicate material, unit is g / cm 3 ; C p is the heat capacity of the high entropy rare earth disilicate material, in J·g -1 ·K -1 , the error is less than 0.1%.

[0108] The thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 1 is as follows: Figure 3 As shown by Figure 3 It can be seen that with the increase of temperature, the thermal conductivity of high entropy rare earth disilicate material shows a downward trend, with the lowest value being 1.81 W·m -1 ·K -1 , which proves that the method of the present invention can successfully prepare the low thermal conductivity (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 environmental barrier coating material.

[0109] The thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 2 is as follows: Figure 7 As shown by Figure 7 It can be seen that the thermal conductivity of the high entropy rare earth disilicate material prepared in Example 2 is the lowest at 1.83 W·m -1 ·K -1 .

[0110] The thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 3 is as follows: Figure 11 As shown by Figure 11 It can be seen that the thermal conductivity of the high entropy rare earth disilicate material prepared in Example 3 is the lowest at 1.89 W·m -1 ·K -1 .

[0111] The thermal conductivity spectrum of the high entropy rare earth disilicate material prepared in Example 4 is as follows: Figure 15 As shown by Figure 15 It can be seen that the thermal conductivity of the high entropy rare earth disilicate material prepared in Example 4 is as low as 1.95 W·m -1 ·K -1 .

[0112] (4) High temperature CMAS corrosion test

[0113] CaO, MgO, AlO3 and SiO2 powders were mixed and sintered in a stoichiometric ratio of 33CaO-9MgO-13AlO-45SiO2 to prepare CMAS powder; 0.0253 g of the prepared CMAS powder was mixed with 1 g of ethanol at a concentration of 30 mg / cm 2 The ethanol was evenly coated on the high entropy rare earth disilicate material prepared in the embodiment; the ethanol was placed in a drying oven to dry the ethanol, and then the sample to be corroded was placed in a muffle furnace at a temperature of 1300°C and a heating rate of 5°C / min for a 48h corrosion experiment.

[0114] The cross-sectional SEM images of the high entropy rare earth disilicate material prepared in Example 1 after being corroded at 1300°C for 48 hours are shown in FIG. Figure 4 As shown in Figure 1, after the high entropy rare earth disilicate material prepared in Example 1 was corroded at 1300 ° C for 48 hours, the average corrosion layer thickness was only 17 μm, and the generated apatite barrier layer was relatively dense, which effectively improved the high temperature CMAS corrosion resistance, proving that this method was successfully used to prepare a high temperature CMAS corrosion resistant (Lu 1 / 8 Yb 1 / 8 Sc 1 / 8 Er 1 / 8 Y 1 / 8 Ho 1 / 8 Dy 1 / 8 Tb 1 / 8 )2Si2O7 coating material.

[0115] The cross-sectional SEM images of the high entropy rare earth disilicate material prepared in Example 2 after being corroded at 1300°C for 48 hours are shown in FIG. Figure 8 As shown, after the high entropy rare earth disilicate material prepared in Example 2 was corroded at 1300° C. for 48 hours, the average corrosion layer thickness was 20 μm.

[0116] The cross-sectional SEM images of the high entropy rare earth disilicate material prepared in Example 3 after being corroded at 1300°C for 48 hours are shown in FIG. Figure 12 As shown, after the high entropy rare earth disilicate material prepared in Example 3 was corroded at 1300° C. for 48 hours, the average corrosion layer thickness was 22 μm.

[0117] The cross-sectional SEM spectrum of the high entropy rare earth disilicate material prepared in Example 4 after being corroded at 1300°C for 48 hours is as follows: Figure 16 As shown, after the high entropy rare earth disilicate material prepared in Example 4 was corroded at 1300° C. for 48 hours, the average corrosion layer thickness was 24 μm.

[0118] The properties of existing ceramic materials are shown in Table 1:

[0119] Table 1 Summary of properties of existing ceramic materials

[0120]

[0121]

[0122] The high-entropy rare earth disilicate material prepared by the present invention has excellent CMAS corrosion resistance under the same conditions.

[0123] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high entropy rare earth disilicate material with the molecular formula (xRE 1 / X )2Si2O7; RE includes four or more of Lu, Yb, Sc, Er, Y, Ho, Dy and Tb; x ranges from 4 to 8; The high entropy rare earth disilicate material is a β monoclinic phase; The preparation method of the high entropy rare earth disilicate material comprises the following steps: (1) SiO2 and RE2O3 are mixed according to (xRE 1 / X )2Si2O7 in a stoichiometric ratio to obtain a mixed powder; (2) The mixed powder is subjected to a first sintering and ball milling to obtain (xRE 1 / X )2Si2O7 ceramic powder; (3) The (xRE 1 / X )2Si2O7 ceramic powder is pressed to obtain (xRE 1 / X )2Si2O7 ceramic block; (4) the (xRE 1 / X )2Si2O7 ceramic block is subjected to a second sintering to obtain the high entropy rare earth disilicate material; Step (2) The first sintering temperature is 1400-1600° C. and the holding time is 3-5 hours; In step (4), the temperature of the second sintering is 1500-1700° C., and the holding time is 5-15 hours.

2. The high entropy rare earth disilicate material according to claim 1, characterized in that The elements in the RE are in an equal molar ratio or a nearly equal molar ratio.

3. The method for preparing the high entropy rare earth disilicate material according to any one of claims 1 to 2, comprising the following steps: (1) SiO2 and RE2O3 are mixed according to (xRE 1 / X )2Si2O7 in a stoichiometric ratio to obtain a mixed powder; (2) The mixed powder is subjected to a first sintering and ball milling to obtain (xRE 1 / X )2Si2O7 ceramic powder; (3) The (xRE 1 / X )2Si2O7 ceramic powder is pressed to obtain (xRE 1 / X )2Si2O7 ceramic block; (4) the (xRE 1 / X )2Si2O7 ceramic block is subjected to a second sintering to obtain the high entropy rare earth disilicate material; Step (2) The first sintering temperature is 1400-1600° C. and the holding time is 3-5 hours; In step (4), the temperature of the second sintering is 1500-1700° C., and the holding time is 5-15 hours.

4. The preparation method according to claim 3, characterized in that The mixing in step (1) is wet ball milling mixing.

5. The preparation method according to claim 4, characterized in that The grinding balls used in the wet ball milling include large-sized zirconia balls, medium-sized zirconia balls and small-sized zirconia balls; the size of the large-sized zirconia balls is Φ7-9mm; the size of the medium-sized zirconia balls is Φ4-6mm; the size of the small-sized zirconia balls is Φ2-4mm; the mass ratio of the large-sized zirconia balls, medium-sized zirconia balls and small-sized zirconia balls is 1:1-3:1; The rotation speed of the wet ball milling is 350-450 rpm, and the ball milling time is 10-12 hours.

6. The preparation method according to claim 3, characterized in that Step (2), the heating rate from room temperature to the first sintering temperature is 3 to 6°C / min.

7. The preparation method according to claim 3, characterized in that The pressing pressure in step (3) is 3-6 MPa, and the holding time is 3-6 min.

8. The preparation method according to claim 3, characterized in that Step (4), the heating rate from room temperature to the second sintering temperature is 4 to 8°C / min.

9. Use of the high-entropy rare earth disilicate material according to any one of claims 1 to 2 or the high-entropy rare earth disilicate material prepared by the preparation method according to any one of claims 3 to 8 in environmental barrier coatings.

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