A high-infrared emissivity Co-doped rare earth tantalate ceramic material with adjustable emissivity, a preparation method and application thereof

Abstract

This invention discloses a high infrared emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity, its preparation method, and its application, belonging to the technical field of thermal barrier coating ceramic materials. The general chemical formula of the ceramic material is RE. 3‑x Co x TaO7, where RE is one of La, Y, Dy, and Yb, with 0.1 ≤ x ≤ 0.5. This invention significantly improves the infrared emissivity of defective fluorite-type rare-earth tantalate ceramic materials by doping with Co at the A-site, achieving an average emissivity of no less than 90% in the 200-2000 nm wavelength range, effectively enhancing the material's ability to suppress radiative heat transfer. The high infrared emissivity ceramic material prepared by this invention can have its final infrared emissivity effectively adjusted by controlling the amount of Co doping, making its performance flexible, adjustable, and more adaptable. The preparation method of the high infrared emissivity ceramic material of this invention is simple, mature, requires minimal equipment, and uses common oxide powders as raw materials, resulting in low cost and suitability for industrial production and application.

Description

Technical Field

[0001] This invention belongs to the technical field of thermal barrier coating ceramic materials, specifically relating to a high infrared emissivity Co-doped rare earth tantalate ceramic material with adjustable emissivity, its preparation method, and its application. Background Technology

[0002] Thermal barrier coatings (TBCs) are critical ceramic protective layers deposited on the surfaces of hot-end components such as aero-engines and gas turbines. They can significantly reduce the service temperature of the metal substrate, thereby effectively extending component life. With the ever-increasing performance requirements of aerospace and energy systems, especially as equipment such as gas turbines develop towards higher thrust-to-weight ratios, the environments faced by their hot-end components are becoming increasingly harsh. Therefore, developing a new generation of thermal barrier coating materials capable of withstanding higher operating temperatures and possessing superior thermal insulation capabilities has become a current research focus.

[0003] The thermal insulation performance of thermal barrier coatings is determined by two core factors: the material's inherent thermal conductivity and its ability to modulate thermal radiation at high temperatures. As temperature increases, the heat transfer contribution of thermal radiation (especially concentrated in the near-infrared band, such as 200-2000 nm) increases significantly. If the ceramic coating has high transmittance or low emissivity in the corresponding wavelength band, the heat from the high-temperature combustion gas will directly penetrate the coating and reach the metal substrate in the form of radiation, producing a radiative heat transmission effect and severely reducing the thermal insulation effect. Therefore, ideal advanced thermal barrier coating materials must simultaneously possess low thermal conductivity and high infrared emissivity. High emissivity means that the coating can efficiently re-emit the absorbed heat in the form of radiation, thereby enhancing surface heat dissipation and improving the thermal management of components at high temperatures.

[0004] Among numerous candidate materials, rare-earth tantalates (such as RE3TaO7) show promise due to their low thermal conductivity. However, similar to classic systems such as yttrium-stabilized zirconium oxide (YSZ) and rare-earth zirconates (RE2Zr2O7), their intrinsic infrared emissivity is generally low, resulting in limited ability to suppress radiative heat transfer at high temperatures and making it difficult to meet the requirements for higher thermal insulation performance. Therefore, effectively improving the emissivity of rare-earth tantalate materials in the near-mid-infrared band is crucial for the development of advanced thermal barrier coating technology. To address the above problems, this invention aims to provide a high-infrared-emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity. Summary of the Invention

[0005] To address the aforementioned problems, the first objective of this invention is to provide a high infrared emissivity Co-doped rare earth tantalate ceramic material with tunable emissivity, and the second objective of this invention is to provide a method for preparing and applying the aforementioned high infrared emissivity Co-doped rare earth tantalate ceramic material.

[0006] The first objective of this invention is achieved by providing a high infrared emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity, the general chemical formula of which is RE. 3-x Co x TaO7, where RE is one of La, Y, Dy, and Yb, and 0.1 ≤ x ≤ 0.5.

[0007] The second objective of this invention is achieved by the method for preparing the high infrared emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity, which is implemented according to the following steps: S1. According to the elemental composition of the ceramic material, RE2O3, CoO, and Ta2O5 powders are mixed and ball-milled to obtain a mixed slurry; S2. The mixed slurry is dried, sieved, and then pre-calcined. The pre-calcined product is then ground and sieved to obtain mixed powder A. The pre-calcination conditions are as follows: the temperature is increased to 1000℃ at a rate of 6-10℃ / min and held for 20-30min; then the temperature is increased to 1200℃ at a rate of 4-6℃ / min and held for 20-30min; finally, the temperature is pre-calcined at 1200-1400℃ at a rate of 2-4℃ / min for 1-4h. S3. The mixed powder A is ball-milled a second time, then dried at a constant temperature, and then sieved a second time to obtain mixed powder B. S4. The mixed powder B is subjected to tableting and cold isostatic pressing to obtain a ceramic blank. S5. The ceramic preform is placed in a muffle furnace for sintering to obtain a high infrared emissivity Co-doped rare earth tantalate ceramic material with adjustable target emissivity.

[0008] The application of the high infrared emissivity Co-doped rare earth tantalate ceramic material with adjustable emissivity is in the preparation of thermal barrier coatings.

[0009] The beneficial effects of this invention are as follows: 1. This invention significantly improves the ultraviolet-visible-near-infrared emissivity of defective fluorite-type rare earth tantalate (RE3TaO7) ceramic materials by doping with Co at the A site. The average emissivity in the 200-2000nm band is not less than 90%, which effectively enhances the ability of rare earth tantalate (RE3TaO7) ceramic materials to suppress radiative heat transfer.

[0010] 2. The high infrared emissivity ceramic material prepared by this invention can effectively adjust the final infrared emissivity of the material by controlling the amount of Co doping, making its performance flexible and adjustable, thus adapting to different application scenarios and making it more adaptable.

[0011] 3. The preparation process of the high infrared emissivity ceramic material of the present invention is simple, the conditions are controllable, the equipment requirements are low, and common oxide powders are used as raw materials, which is inexpensive and suitable for industrial production and application. Attached Figure Description

[0012] Figure 1 These are the phase and emissivity characterization diagrams of the Co-doped rare earth tantalate ceramic material prepared in Example 1 of this invention, where (a) is an X-ray diffraction pattern and (b) is an emissivity pattern.

[0013] Figure 2 These are the phase and emissivity characterization diagrams of the Co-doped rare earth tantalate ceramic material prepared in Example 2 of the present invention, wherein (a) is an X-ray diffraction pattern and (b) is an emissivity pattern.

[0014] Figure 3 These are the phase and emissivity characterization diagrams of the Co-doped rare earth tantalate ceramic material prepared in Example 3 of the present invention, wherein (a) is an X-ray diffraction pattern and (b) is an emissivity pattern.

[0015] Figure 4 These are the phase and emissivity characterization diagrams of the Co-doped rare earth tantalate ceramic material prepared in Example 4 of this invention, where (a) is an X-ray diffraction pattern and (b) is an emissivity pattern.

[0016] Figure 5 These are the phase and emissivity characterization diagrams of the Co-doped rare earth tantalate ceramic material prepared in Example 5 of the present invention, wherein (a) is an X-ray diffraction pattern and (b) is an emissivity pattern. Detailed Implementation

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments, but this does not limit the present invention in any way. Any modifications or improvements made based on the teachings of the present invention shall fall within the protection scope of the present invention.

[0018] This invention provides a high infrared emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity, the general chemical formula of which is RE. 3-x Co x TaO7, where RE is one of La, Y, Dy, and Yb, and 0.1 ≤ x ≤ 0.5.

[0019] The ceramic material has a grain size of 0.5-5 μm and a porosity of less than 5%; the ceramic material has an average emissivity of ≥90% in the 200-2000 nm wavelength band.

[0020] This invention also provides a method for preparing the aforementioned high infrared emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity, the method comprising the following steps: S1. According to the elemental composition of the ceramic material, RE2O3, CoO, and Ta2O5 powders are mixed and ball-milled to obtain a mixed slurry; S2. The mixed slurry is dried, sieved, and then pre-calcined. The pre-calcined product is then ground and sieved to obtain mixed powder A. The pre-calcination conditions are as follows: the temperature is increased to 1000℃ at a rate of 5-10℃ / min and held for 20-30min; then the temperature is increased to 1200℃ at a rate of 2-5℃ / min and held for 20-30min; finally, it is pre-calcined at 1200-1400℃ for 1-4h. S3. The mixed powder A is ball-milled a second time, then dried at a constant temperature, and then sieved a second time to obtain mixed powder B. S4. The mixed powder B is subjected to tableting and cold isostatic pressing to obtain a ceramic blank. S5. The ceramic preform is placed in a muffle furnace for sintering to obtain a high infrared emissivity Co-doped rare earth tantalate ceramic material with adjustable target emissivity.

[0021] In step S5, the sintering process is as follows: reacting at 1500-1650℃ for 4-12 hours in an air atmosphere.

[0022] In steps S1 and S3, the ball milling speed is 200-600 r / min, the ball milling time is 12-24 h, and the ball milling mode is alternating between forward and reverse rotation for 15-30 min, without any pause in between.

[0023] In step S2, the grinding time is 5-10 minutes and the sieve mesh size is 100-300 mesh.

[0024] In step S4, the tableting process is carried out under a pressure of 10-20 MPa for 5-10 minutes, and the cold isostatic pressing process is carried out under a pressure of 100-300 MPa for 2-5 minutes.

[0025] The present invention further provides the application of the high infrared emissivity Co-doped rare earth tantalate ceramic material with tunable emissivity in the preparation of thermal barrier coatings.

[0026] Example 1 The chemical formula is La 2.9 Co 0.1 The preparation method of TaO7 high infrared emissivity ceramic material includes the following steps: (1) The La2O3, CoO and Ta2O3 powder raw materials were dried at 60℃ for 12 hours to remove adsorbed water; (2) Weigh the above dry powder according to the molar ratio of La:Co:Ta=2.9:0.1:1, place it in a ball mill jar, add anhydrous ethanol and zirconium oxide grinding balls, and ball mill at a speed of 350 r / min for 20 hours, alternating forward and reverse rotation every 15 minutes to obtain a mixed slurry; (3) The mixed slurry was dried at 70°C for 20 hours and passed through a 200-mesh sieve. The sieved powder was placed in a muffle furnace for pre-calcination: the temperature was increased to 1000°C at 8°C / min and held for 20 minutes, then increased to 1200°C at 5°C / min and held for 20 minutes, then increased to 1350°C at 3°C / min and held for 3 hours, and finally cooled with the furnace. The pre-calcined product was ground for 5 minutes and passed through a 200-mesh sieve to obtain mixed powder A; (4) The mixed powder A is ball-milled again under the same conditions as in step (2). The slurry after ball milling is dried at 70°C for 20 hours and passed through a 300-mesh sieve to obtain mixed powder B. (5) The mixed powder B is pressed into a sheet at a pressure of 15 MPa and held for 8 minutes to obtain a ceramic green body. The green body is then subjected to cold isostatic pressing at a pressure of 250 MPa and held for 2 minutes to obtain a dense ceramic body; (6) The dense ceramic body is placed in a muffle furnace and sintered at 1620℃ for 8 hours in air atmosphere. The temperature is increased to 1000℃ at room temperature at 8℃ / min and held for 25 min, then increased to 1200℃ at 5℃ / min and held for 25 min, then increased to 1400℃ at 3℃ / min and held for 25 min, and finally increased to 1620℃ at 2℃ / min and held for 8 hours. After cooling in the furnace, La is obtained. 2.9 Co 0.1 TaO7 ceramic material. Testing showed that the grain size of this material is approximately 1-3 μm; the porosity is approximately 3%; and it is composed of… Figure 1 As can be seen in (a), the ceramic material has a layered perovskite structure and no obvious impurity phases.

[0027] Example 2 The chemical formula is La 2.5 Co 0.5 The preparation method of TaO7 high infrared emissivity ceramic material includes the following steps: (1) The La2O3, CoO and Ta2O3 powder raw materials were dried at 60℃ for 12 hours to remove adsorbed water; (2) Weigh the above dry powder according to the molar ratio of La:Co:Ta=2.5:0.5:1, place it in a ball mill jar, add anhydrous ethanol and zirconium oxide grinding balls, and ball mill at a speed of 350 r / min for 20 hours, alternating forward and reverse rotation every 15 minutes to obtain a mixed slurry; (3) Dry the mixed slurry at 70°C for 20 hours and pass it through a 200-mesh sieve. Place the sieved powder in a muffle furnace for pre-calcination, raise the temperature to 1000°C at 8°C / min and hold for 20 minutes, then raise the temperature to 1200°C at 5°C / min and hold for 20 minutes, then raise the temperature to 1350°C at 3°C / min and hold for 3 hours, and cool with the furnace. Grind the pre-calcined product for 5 minutes and pass it through a 200-mesh sieve to obtain mixed powder A; (4) The mixed powder A is ball-milled again under the same conditions as in step (2). The slurry after ball milling is dried at 70°C for 20 hours and passed through a 300-mesh sieve to obtain mixed powder B. (5) The mixed powder B is pressed into a sheet at a pressure of 15 MPa and held for 8 minutes to obtain a green body. The green body is then subjected to cold isostatic pressing at a pressure of 250 MPa and held for 2 minutes to obtain a dense ceramic body; (6) The ceramic body is placed in a muffle furnace and sintered at 1620℃ for 12 hours in air atmosphere. The temperature is increased to 1000℃ at room temperature at 8℃ / min and held for 20 min, then increased to 1200℃ at 5℃ / min and held for 20 min, then increased to 1400℃ at 3℃ / min and held for 20 min, and finally increased to 1620℃ at 2℃ / min and held for 12 hours. After cooling in the furnace, La is obtained. 2.5 Co 0.5 TaO7 ceramic material. Testing showed that this material has a grain size of approximately 1-3 μm and a porosity of approximately 1.5%. Figure 2 As can be seen in (a), it has a layered perovskite structure with no obvious impurities.

[0028] Example 3 The chemical formula is Y 2.8 Co 0.2 The preparation method of TaO7 high infrared emissivity ceramic material includes the following steps: (1) The Y2O3, CoO and Ta2O5 powder raw materials were dried at 80℃ for 24 hours to remove adsorbed water; (2) Weigh the above dry powder according to the molar ratio of Y:Co:Ta=2.8:0.2:1, place it in a ball mill jar, add anhydrous ethanol and zirconium oxide grinding balls, and ball mill at a speed of 400 r / min for 24 hours, alternating forward and reverse rotation every 20 minutes to obtain a mixed slurry; (3) Dry the slurry at 80℃ for 24 hours and pass it through a 200-mesh sieve. Place the sieved powder in a muffle furnace for pre-calcination: raise the temperature to 1000℃ at 10℃ / min and hold for 20 minutes, then raise the temperature to 1200℃ at 6℃ / min and hold for 20 minutes, then raise the temperature to 1300℃ at 3℃ / min and hold for 2 hours, and cool with the furnace. Grind the pre-calcined product for 10 minutes and pass it through a 200-mesh sieve to obtain mixed powder A; (4) The mixed powder A is ball-milled again under the same conditions as in step (2). The slurry after ball milling is dried at 80°C for 24 hours and passed through a 300-mesh sieve to obtain mixed powder B. (5) The mixed powder B is pressed into a sheet under a pressure of 20 MPa and held for 5 minutes to obtain a green body. The green body is then subjected to cold isostatic pressing at a pressure of 200 MPa and held for 3 minutes to obtain a dense ceramic body; (6) Place the ceramic body in a muffle furnace and sinter it at 1600℃ for 6 hours in an air atmosphere. The temperature is increased to 1000℃ at room temperature at 10℃ / min and held for 30 min, then increased to 1200℃ at 6℃ / min and held for 30 min, then increased to 1400℃ at 3℃ / min and held for 30 min, and finally increased to 1600℃ at 2℃ / min and held for 6 hours. After cooling in the furnace, Y is obtained. 2.8 Co 0.2 TaO7 ceramic material. Testing showed that this material has a grain size of approximately 1-3 μm and a porosity of approximately 2%. Figure 3 As can be seen in (a), it has a layered perovskite structure with no obvious impurities.

[0029] Example 4 The chemical formula is Dy 2.7 Co 0.3 The preparation method of TaO7 high infrared emissivity ceramic material includes the following steps: (1) The Dy2O3, CoO and Ta2O5 powder raw materials were dried at 80℃ for 18 hours to remove adsorbed water; (2) Weigh the above dry powder according to the molar ratio of Dy:Co:Ta=2.7:0.0.3:1, place it in a ball mill jar, add anhydrous ethanol and zirconium oxide grinding balls, and ball mill at a speed of 500 r / min for 18 hours (alternating forward and reverse rotation every 30 minutes) to obtain a mixed slurry; (3) Dry the mixed slurry at 80°C for 18 hours and pass it through a 200-mesh sieve. Place the sieved powder in a muffle furnace for pre-calcination: raise the temperature to 1000°C at 6°C / min and hold for 30 minutes, then raise the temperature to 1200°C at 4°C / min and hold for 30 minutes, then raise the temperature to 1400°C at 3°C / min and hold for 1 hour, and cool with the furnace. Grind the pre-calcined product for 8 minutes and pass it through a 200-mesh sieve to obtain mixed powder A; (4) The mixed powder A is ball-milled again under the conditions of step (2). The slurry after ball milling is dried at 80°C for 18 hours and passed through a 300-mesh sieve to obtain mixed powder B. (5) The mixed powder B is pressed into a sheet under a pressure of 20 MPa and held for 5 minutes to obtain a green body. The green body is then subjected to cold isostatic pressing at a pressure of 300 MPa and held for 5 minutes to obtain a dense ceramic body; (6) The ceramic body is placed in a muffle furnace and sintered at 1580℃ for 4 hours in an air atmosphere. The temperature is increased to 1000℃ at room temperature at 6℃ / min and held for 25 min, then increased to 1200℃ at 4℃ / min and held for 25 min, then increased to 1400℃ at 3℃ / min and held for 25 min, and finally increased to 1580℃ at 2℃ / min and held for 4 hours. After cooling in the furnace, Dy is obtained. 2.7 Co 0.3 TaO7 ceramic material. Testing showed that this material has a grain size of approximately 0.5-2 μm and a porosity of approximately 3%. Figure 4 As can be seen in (a), it has a layered perovskite structure with no obvious impurities.

[0030] Example 5 The chemical formula is Yb 2.6 Co 0.4 The preparation method of TaO7 high infrared emissivity ceramic material includes the following steps: (1) The Yb2O3, CoO and Ta2O5 powder raw materials were dried at 70℃ for 20 hours to remove adsorbed water; (2) Weigh the above dry powder according to the molar ratio of Yb:Co:Ta=2.6:0.4:1, place it in a ball mill jar, add anhydrous ethanol and zirconium oxide grinding balls, and ball mill at a speed of 450 r / min for 20 hours (alternating forward and reverse rotation every 25 minutes) to obtain a mixed slurry; (3) Dry the mixed slurry at 75°C for 20 hours and pass it through a 200-mesh sieve. Place the sieved powder in a muffle furnace for pre-calcination: raise the temperature to 1000°C at 9°C / min and hold for 20 minutes, then raise the temperature to 1200°C at 5°C / min and hold for 20 minutes, then raise the temperature to 1200°C at 3°C / min and hold for 4 hours, and cool with the furnace. Grind the pre-calcined product for 10 minutes and pass it through a 200-mesh sieve to obtain mixed powder A; (4) The mixed powder A is ball-milled again according to the conditions in step (2). The slurry after ball milling is dried at 75°C for 20 hours and passed through a 300-mesh sieve to obtain mixed powder B. (5) The mixed powder B is pressed into a sheet under a pressure of 10 MPa and held for 10 minutes to obtain a green body. The green body is then subjected to cold isostatic pressing at a pressure of 150 MPa and held for 4 minutes to obtain a dense ceramic body; (6) The ceramic body is placed in a muffle furnace and sintered at 1550℃ for 4 hours in an air atmosphere. The temperature is increased to 1000℃ at room temperature at 9℃ / min and held for 25 min, then increased to 1200℃ at 5℃ / min and held for 25 min, then increased to 1400℃ at 3℃ / min and held for 25 min, and finally increased to 1550℃ at 2℃ / min and held for 4 hours. After cooling in the furnace, Yb is obtained. 2.6 Co 0.4 TaO7 ceramic material. Testing showed that this material has a grain size of approximately 1-4 μm and a porosity of approximately 4%. Figure 5 As can be seen in (a), it has a layered perovskite structure with no obvious impurities.

[0031] Test Example 1: Performance testing of ceramic materials prepared in Examples 1-5 1. The reflectance ρ of the ceramic materials prepared in Examples 1-5 was measured using a UV-3600 Plus ultraviolet-visible-near-infrared spectrometer, and their emissivity was calculated according to Kirchhoff's thermal radiation law. The average emissivity results of the ceramic materials prepared in Examples 1-5 in the 200-2000nm wavelength range are shown in Table 1.

[0032] 2. The thermal diffusivity of the ceramic materials prepared in Examples 1-5 was measured at 900°C using an LFA457 instrument, and the thermal conductivity data were obtained using the Kelemen equation. The oxygen ion conductivity was tested using an electrochemical workstation, and the activation energy of the material was obtained by linear fitting based on the Aronunis equation and the slope was taken. The test results are shown in Table 1.

[0033] 3. The hardness and fracture toughness of the ceramic materials prepared in Examples 1-5 were tested using a Vickers hardness indenter HMV-G-FA. A load of 500mN was applied and the holding time was 10s. The test results are shown in Table 1.

[0034] 4. The elastic modulus of the ceramic materials prepared in Examples 1-5 was determined by using an ultrasonic reflection device UMS-100.

[0035] Table 1 Performance data of ceramic materials prepared in Examples 1-5

[0036] Results analysis: As shown in Table 1, the method of this invention successfully prepared a ceramic material RE that combines high infrared emissivity, low thermal conductivity, good mechanical properties, and high thermal stability. 3-x Co xTaO7 (RE=Y, L, Dy, Yb; 0.1≤x≤0.5). The ceramic material of this invention has an average emissivity of over 90% in the 200-2000nm wavelength range, meeting the high emissivity requirement for high thermal barrier performance. Example 1 (La...) 2.9 Co 0.1 TaO7 (emissivity 91.5%) and Example 2 (La) 2.5 Co 0.5 In the case of TaO7 (with an emissivity of 95.1%), where the rare earth element is La, the infrared emissivity of the material significantly increases as the Co doping amount (x) increases from 0.1 to 0.5, indicating that the infrared emissivity of the material can be flexibly controlled by adjusting the Co doping amount. Simultaneously, the ceramic material of this invention exhibits excellent thermophysical and mechanical properties, with an activation energy of 1.42-1.83 eV, higher than the 1.34 eV of Sm3TaO7. This demonstrates that Co doping effectively improves the high-temperature structural stability of the material, enabling long-term stable service and significantly extending the service life of the coating.

[0037] The specific embodiments of the present invention have been described in detail above, but these are merely examples, and the present invention is not limited to the specific embodiments described above. For those skilled in the art, any equivalent modifications or substitutions to the invention are also within the scope of the present invention. Therefore, all equivalent transformations, modifications, and improvements made without departing from the spirit and principles of the present invention should be covered within the scope of the present invention.

Claims

1. A high infrared emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity, characterized in that, The general chemical formula of the ceramic material is RE 3-x Co x TaO7, where RE is one of La, Y, Dy, and Yb, and 0.1 ≤ x ≤ 0.

5.

2. The high infrared emissivity Co-doped rare-earth tantalate ceramic material with tunable emissivity according to claim 1, characterized in that, The ceramic material has a grain size of 0.5-5 μm and a porosity of less than 5%; the ceramic material has an average emissivity of ≥90% in the 200-2000 nm wavelength band.

3. The method for preparing the high infrared emissivity Co-doped rare earth tantalate ceramic material with tunable emissivity according to claim 1, characterized in that, The preparation method of the ceramic material is carried out according to the following steps: S1. According to the elemental composition of the ceramic material, RE2O3, CoO, and Ta2O5 powders are mixed and ball-milled to obtain a mixed slurry; S2. The mixed slurry is dried, sieved, and then pre-calcined. The pre-calcined product is then ground and sieved to obtain mixed powder A. The pre-calcination conditions are as follows: the temperature is increased to 1000℃ at a rate of 6-10℃ / min and held for 20-30min; then the temperature is increased to 1200℃ at a rate of 4-6℃ / min and held for 20-30min; finally, the temperature is increased to 1200-1400℃ at a rate of 2-4℃ / min and held for 1-4h. S3. The mixed powder A is ball-milled a second time, then dried at a constant temperature, and then sieved a second time to obtain mixed powder B. S4. The mixed powder B is subjected to tableting and cold isostatic pressing to obtain a ceramic blank. S5. The ceramic preform is placed in a muffle furnace for sintering to obtain a high infrared emissivity Co-doped rare earth tantalate ceramic material with adjustable target emissivity.

4. The preparation method according to claim 3, characterized in that, In step S5, the sintering process is as follows: reacting at 1500-1650℃ for 4-12 hours in an air atmosphere.

5. The preparation method according to claim 3, characterized in that, In steps S1 and S3, the ball milling speed is 200-600 r / min, the ball milling time is 12-24 h, and the ball milling mode is alternating between forward and reverse rotation for 15-30 min, without any pause in between.

6. The preparation method according to claim 3, characterized in that, In step S2, the grinding time is 5-10 minutes and the sieve mesh size is 100-300 mesh.

7. The preparation method according to claim 3, characterized in that, In step S4, the tableting process is carried out under a pressure of 10-20 MPa for 5-10 minutes, and the cold isostatic pressing process is carried out under a pressure of 100-300 MPa for 2-5 minutes.

8. The application of the high infrared emissivity Co-doped rare earth tantalate ceramic material with tunable emissivity as described in claim 1 in the preparation of thermal barrier coatings.

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