ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating with both infrared radiation shielding and high emissivity and a preparation method thereof

Abstract

The application discloses an ABO3 type transition group metal oxide composite rare earth tantalate ceramic / coating with infrared radiation shielding and high emissivity and a preparation method thereof, and belongs to the technical field of thermal barrier coating materials. The ABO3 type transition group metal oxide composite rare earth tantalate ceramic / coating with infrared radiation shielding and high emissivity prepared by the application is ABO3 type transition group metal oxide with intrinsic high absorption characteristics which is dispersedly distributed in a rare earth tantalate ceramic base phase. The ABO3 type transition group metal oxide composite tantalate ceramic and coating with infrared radiation shielding and high emissivity prepared by the application has ultralow infrared transmittance (T <= 0.2%) in the wavelength range of 400-2500 nm, has excellent infrared radiation shielding characteristics, the average emissivity in the infrared wave band (2.5-14 mu m) is greater than 0.9, and the upward trend of high-temperature (>= 800 DEG C) thermal conductivity is obviously inhibited, which is of great significance.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal barrier coating materials, and specifically relates to an ABO3-type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity, and a preparation method thereof. Background Art

[0002] Thermal barrier coatings (TBCs) are commonly used to protect hot-end components exposed to high-temperature heat fluxes, such as the outer skins of hypersonic vehicles, aircraft engines, and large gas turbine blades. This allows these systems to operate stably in high-temperature environments and improves their performance and efficiency. Rare earth tantalates (RTCs) offer great potential as thermal barrier coatings due to their low thermal conductivity, excellent phase stability and corrosion resistance, suitable thermal expansion coefficients, and excellent mechanical properties. However, like common TBCs (Turbine Bearing Coatings) (TBCs), they are semi-transparent to infrared radiation in the short infrared range, meaning that thermal radiation generated by external high-temperature heat fluxes can penetrate the coating and cause thermal damage to the substrate. Under a 2000K heat flux, the combined conductive and radiative heat flux within TBCs can be approximately 30% higher than the conductive heat flux alone. This reduction in TBC insulation due to infrared radiation heat transfer is a significant issue. Therefore, improving the radiation penetration resistance of TBC materials is a pressing need for next-generation ultra-high-temperature gas turbine systems. However, research on regulating the radiation penetration resistance of thermal barrier coating material systems is still in its early stages, with relatively few studies. In the past five years, only Chinese patents (CN 115233069 A) and (CN 115010492 A) have disclosed composite materials comprising parallel platinum microplatelets and a dispersed noble metal nanoparticle matrix within a ceramic matrix, as well as methods for preparing the same, to improve the infrared radiation shielding performance of ceramics. The selection of a noble metal second phase presents challenges such as high cost, poor thermal expansion matching between the noble metal and the ceramic matrix, and increased thermal conductivity. Therefore, efforts are underway to develop thermal barrier coating ceramic materials and coating preparation methods that combine low cost, high radiation penetration resistance, a high coefficient of thermal expansion, and low thermal conductivity for infrared radiation shielding. Summary of the Invention

[0003] The purpose of the present invention is to solve the problems that the infrared transmittance of the diffuse second phase anti-radiation penetration coating in the infrared radiation shielding thermal barrier coating material prepared by the existing method is not low enough, the low infrared transmittance material composited with precious metal nanoparticles has high economic cost, and the thermal expansion coefficient of the doped precious metal second phase and the base phase is quite different, which leads to thermal mismatch in actual application of the thermal barrier coating, easily causing failure at the interface between the coating and the substrate, and reducing its stability under high-temperature service. The present invention provides an ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating with both infrared radiation shielding and high emissivity and a preparation method thereof.

[0004] The invention relates to an ABO3-type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity. The ABO3-type transition metal oxide with intrinsic high absorption characteristics is dispersed in the rare earth tantalate ceramic matrix phase. The ABO3-type transition metal oxide is stacked in a lamellar structure into a nearly spherical shape with a diameter of 1000 to 1500 nm. The ABO3-type transition metal oxide and the rare earth tantalate ceramic matrix phase belong to different crystal systems, and there is no infinite solid solution effect between the two.

[0005] A method for preparing an ABO3-type transition metal oxide composite rare earth tantalate ceramic having both infrared radiation shielding and high emissivity is specifically completed by the following steps:

[0006] 1. Weighing B2O3 or BO and A2O3, uniformly mixing the weighed B2O3 or BO and A2O3 to obtain mixed powder I, and calcining the mixed powder I to obtain ABO3 type transition metal oxide powder;

[0007] The A element in A2O3 described in step 1 is Eu, Gd, Tb, Dy or Y; B in B2O3 is Cr or Fe; B in BO is Co or Ni;

[0008] The molar ratio of A2O3 and B2O3 described in step 1 is 1:1;

[0009] The molar ratio of A2O3 and BO described in step 1 is 1:2;

[0010] The calcination process in step 1 is as follows: heating to 1200°C to 1300°C at a heating rate of 3°C / min to 5°C / min, calcining at 1200°C to 1300°C for 4h to 6h, and then cooling to room temperature in the furnace;

[0011] 2. Weighing Re2O3 and Ta2O5, mixing the weighed Re2O3 and Ta2O5 uniformly to obtain mixed powder II, and calcining the mixed powder II to obtain rare earth tantalate-based ceramic powder;

[0012] The molar ratio of Re2O3 and Ta2O5 described in step 2 is 3:1;

[0013] The Re element in the Re2O3 in step 2 is Eu, Gd, Tb, Dy or Y;

[0014] The calcination process in step 2 is as follows: heating to 1400°C to 1500°C at a heating rate of 3°C / min to 5°C / min, calcining at 1400°C to 1500°C for 4h to 7h, and then cooling to room temperature in the furnace;

[0015] 3. Weighing ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder, and uniformly mixing the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder to obtain mixed powder III; pre-pressing, cold isostatically pressing, and calcining the mixed powder III to obtain an ABO3 transition metal oxide composite rare earth tantalate ceramic with both infrared radiation shielding and high emissivity;

[0016] The molar ratio of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder described in step 3 is (0.9-0.975):(0.025-0.1);

[0017] The calcination process described in step three is: heating to 1550°C to 1600°C at a heating rate of 3°C / min to 5°C / min, calcining at 1550°C to 1600°C for 8h to 10h, and then cooling to room temperature with the furnace.

[0018] A method for preparing an ABO3-type transition metal oxide composite rare earth tantalate ceramic coating having both infrared radiation shielding and high emissivity is specifically completed by the following steps:

[0019] 1. Pretreatment of substrate:

[0020] Removing impurities and oil stains on the substrate surface and roughening the substrate surface to obtain a pretreated substrate;

[0021] 2. Preparation of bonding layer:

[0022] The pretreated substrate is subjected to high-temperature heat treatment, and then an atmospheric plasma spraying process is used to prepare an adhesive layer on the surface of the heat-treated substrate to obtain a substrate with an adhesive layer attached thereto;

[0023] 3. Granulation treatment:

[0024] The mixed powder III is granulated to obtain an ABO3 type transition metal oxide composite rare earth tantalate feed powder; the ABO3 type transition metal oxide composite rare earth tantalate feed powder is sprayed onto the surface of a substrate to which an adhesive layer is attached using an atmospheric plasma spraying process to obtain an ABO3 type transition metal oxide composite rare earth tantalate coating with both infrared radiation shielding and high emissivity on the surface of the substrate.

[0025] Principle of the present invention:

[0026] The present invention uses a solid-phase reaction combined with a secondary calcination technology to in-situ synthesize uniformly dispersed ABO3 transition metal oxide particles within a rare earth tantalate matrix. Utilizing the intrinsic high optical absorption characteristics of the ABO3 transition metal oxide and the enhanced backscattering of the particles caused by the proximity of the infrared wavelength to the particle size, the infrared radiation shielding ABO3 transition metal oxide composite rare earth tantalate ceramic / coating of the present invention can have an infrared transmittance of less than 0.2% in the near-infrared band of 400-2500 nm and an average emissivity of greater than 0.8 in the near-infrared band (2.5-6 μm), thereby improving the ability of the ceramic matrix phase to resist high-temperature radiation penetration. Moreover, the difference in thermal expansion coefficient between the composite ceramic and the ceramic matrix phase is less than 0.5×10 -6 K -1 , the upward trend of high-temperature thermal conductivity is suppressed, ensuring the high-temperature stability of the thermal barrier coating, thereby improving its service life.

[0027] Advantages of the present invention

[0028] The present invention provides an ABO3-type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity and a preparation method thereof. Compared with existing precious metal nanoparticle composite ceramic systems and dispersed phase composite ceramic systems, the present invention adopts a material system and process technology with lower cost and simpler operation to obtain excellent infrared radiation shielding performance. At the same time, the composite material has good thermal expansion matching and high-temperature service stability, which is of great significance to the development of thermal barrier coatings in the field of resisting infrared radiation penetration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 X-ray diffraction patterns of the ABO3-type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 and the Gd3TaO7 ceramic block prepared in Comparative Example 1;

[0030] Figure 2 Scanning electron microscope (SEM) morphologies and corresponding macroscopic morphologies of the surfaces of the ABO3-type transition metal oxide composite rare earth tantalate ceramic with both infrared radiation shielding and high emissivity prepared in Example 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1, with (a) showing Example 4 and (b) showing Example 1.

[0031] Figure 3 The linear-hemispherical transmittance from 400 nm to 2500 nm of the ABO3-type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1;

[0032] Figure 4Spectral emissivity from 2.5 μm to 14 μm of the ABO3 type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1;

[0033] Figure 5 Thermal conductivity of the ABO3 type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1 at 50°C, 200°C, 400°C, 600°C, 800°C, 1000°C, and 1200°C. DETAILED DESCRIPTION

[0034] Specific embodiment 1: This embodiment is an ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating with both infrared radiation shielding and high emissivity, in which the ABO3 type transition metal oxide with intrinsic high absorption characteristics is dispersed in the rare earth tantalate ceramic matrix phase, and the ABO3 type transition metal oxide is stacked in a lamellar structure into an approximate sphere with a diameter of 1000 to 1500 nm; the ABO3 type transition metal oxide and the rare earth tantalate ceramic matrix phase belong to different crystal systems, and there is no infinite solid solution effect between the two.

[0035] Specific Embodiment 2: This embodiment differs from Specific Embodiment 1 in that the ABO3-type transition metal oxide comprises element A, which is Eu, Gd, Tb, Dy, or Y; element B, which is Cr, Fe, Co, or Ni; and a rare earth tantalate ceramic matrix comprising Re3TaO7 with a Weberian structure, wherein the Re element is Eu, Gd, Tb, Dy, or Y. Re3TaO7 with a Weberian structure exhibits superior mechanical properties and high-temperature thermal expansion compatibility. Other steps are the same as those in Specific Embodiment 1.

[0036] Specific embodiment 3: This embodiment differs from either specific embodiment 1 or 2 in that: the rare earth tantalate ceramic matrix is ​​Re3TaO7 with a Weberian structure, wherein the Re element is Eu, Gd, Tb, Dy, or Y; the ABO3-type transition metal oxide has an AFeO3 structure, characterized by a variable Fe ion valence and a narrow bandgap; and the A element is Eu, Gd, Tb, Dy, or Y; the A element is the same as the Re element in Re3TaO7. Other steps are the same as those in specific embodiments 1 or 2.

[0037] Specific Embodiment 4: This embodiment differs from Specific Embodiments 1 to 3 in that the mass fraction of the ABO3 transition metal oxide in the ABO3 transition metal oxide composite rare earth tantalate ceramic / coating, which combines infrared radiation shielding and high emissivity, is 0.89% to 3.8%. The remaining steps are the same as Specific Embodiments 1 to 3.

[0038] Specific Embodiment 5: This embodiment differs from Specific Embodiments 1 to 4 in that the ABO3-type transition metal oxide composite rare earth tantalate ceramic / coating, which combines infrared radiation shielding and high emissivity, has an ultra-low infrared transmittance of ≤0.2% in the 400-2500 nm band, an average emissivity of >0.9 in the 2.5-14 μm infrared band, an average emissivity of greater than 0.8 in the 2.5-6 μm near-infrared band, and an average emissivity of >0.95 in the 6-14 μm mid-infrared band. The remaining steps are the same as Specific Embodiments 1 to 4.

[0039] Specific embodiment 6: This embodiment differs from specific embodiments 1 to 5 in that the thermal expansion coefficient of the ABO3 transition metal oxide composite rare earth tantalate ceramic / coating with both infrared radiation shielding and high emissivity within the range of 50 to 1400°C is 9.6×10 -6 K -1 ~9.8×10 -6 K -1 , and has a high compatibility with the metal substrate. The other steps are the same as those in the first to fifth embodiments.

[0040] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the preparation method of the ABO3 type transition metal oxide composite rare earth tantalate ceramic with both infrared radiation shielding and high emissivity is specifically completed according to the following steps:

[0041] 1. Weighing B2O3 or BO and A2O3, uniformly mixing the weighed B2O3 or BO and A2O3 to obtain mixed powder I, and calcining the mixed powder I to obtain ABO3 type transition metal oxide powder;

[0042] The A element in A2O3 described in step 1 is Eu, Gd, Tb, Dy or Y; B in B2O3 is Cr or Fe; B in BO is Co or Ni;

[0043] The molar ratio of A2O3 and B2O3 described in step 1 is 1:1;

[0044] The molar ratio of A2O3 and BO described in step 1 is 1:2;

[0045] The calcination process in step 1 is as follows: heating to 1200°C to 1300°C at a heating rate of 3°C / min to 5°C / min, calcining at 1200°C to 1300°C for 4h to 6h, and then cooling to room temperature in the furnace;

[0046] 2. Weighing Re2O3 and Ta2O5, mixing the weighed Re2O3 and Ta2O5 uniformly to obtain mixed powder II, and calcining the mixed powder II to obtain rare earth tantalate-based ceramic powder;

[0047] The molar ratio of Re2O3 and Ta2O5 described in step 2 is 3:1;

[0048] The Re element in the Re2O3 in step 2 is Eu, Gd, Tb, Dy or Y;

[0049] The calcination process in step 2 is as follows: heating to 1400°C to 1500°C at a heating rate of 3°C / min to 5°C / min, calcining at 1400°C to 1500°C for 4h to 7h, and then cooling to room temperature in the furnace;

[0050] 3. Weighing ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder, and uniformly mixing the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder to obtain mixed powder III; pre-pressing, cold isostatically pressing, and calcining the mixed powder III to obtain an ABO3 transition metal oxide composite rare earth tantalate ceramic with both infrared radiation shielding and high emissivity;

[0051] The molar ratio of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder described in step 3 is (0.9-0.975):(0.025-0.1);

[0052] The calcination process in step 3 is as follows: heating to 1550°C to 1600°C at a heating rate of 3°C / min to 5°C / min, calcining at 1550°C to 1600°C for 8 to 10 hours, and then cooling to room temperature. The other steps are the same as those in specific embodiments 1 to 6.

[0053] Specific embodiment eight: This embodiment differs from specific embodiments one to seven in that: the mixing method described in step one is: the weighed B2O3 or BO, A2O3 are placed at 600°C to 900°C for 3h to 6h, and cooled to room temperature with the furnace to obtain B2O3 or BO, A2O3 with impurities and bound water removed; the B2O3 or BO, A2O3 with impurities and bound water removed, anhydrous ethanol and zirconium oxide grinding balls are placed in a ball mill, and then ball milled at a speed of 300 to 500r / min for 12h to 24h, and then dried at 80°C to 100°C for 8h to 12h, ground, and sieved through a 200-mesh to 400-mesh sieve to obtain mixed powder I; step The mass ratio of the total mass of B2O3 or BO, A2O3 from which impurities and bound water have been removed to anhydrous ethanol and zirconia microspheres is 1:(0.1-0.2):(4-6); the diameter of the zirconia microspheres is 1 mm to 3 mm; the mixing method described in step 2 is as follows: weighed Re2O3 and Ta2O5 are calcined at 600°C to 900°C for 3h to 6h, and then cooled to room temperature in the furnace to obtain Re2O3 and Ta2O5 from which impurities and bound water have been removed; the Re2O3, Ta2O5 from which impurities and bound water have been removed, anhydrous ethanol and zirconia grinding balls are placed in a ball mill, and then ball milled at a speed of 300-500 r / min for 12h to 24h, then dried at 80℃~100℃ for 8h~12h, ground, and passed through a 200-400 mesh sieve to obtain a mixed powder II; the mass ratio of the total mass of Re2O3 and Ta2O5 from which impurities and bound water are removed in step 2 to anhydrous ethanol and zirconia microspheres is 1:(0.1~0.2):(4~6); the diameter of the zirconia microspheres is 1~3mm; the mixing method described in step 3 is: ABO3 type transition metal oxide powder, rare earth tantalate-based ceramic powder, anhydrous ethanol and zirconia grinding balls are placed in a ball mill, and then ball milled at a speed of 300~500r / min for 10h~15h, and then at 60℃~100℃ Dry for 10 to 15 hours, grind, and pass through a 300-400 mesh sieve to obtain a mixed powder III; the mass ratio of the total mass of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder, anhydrous ethanol, and zirconium oxide microspheres described in step 3 is 1:(0.1-0.2):(4-6); the diameter of the zirconium oxide microspheres is 1-3 mm; the pre-pressing molding described in step 3 is: using a press to pre-press the mixed powder III into a columnar block, the pressure is 10-12 MPa, and the pressure is maintained for 3 to 5 minutes; the cold isostatic pressing pressure described in step 3 is 200 MPa-250 MPa, and the pressure is maintained for 3 to 5 minutes. The other steps are the same as those in specific embodiments one to seven.

[0054] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the method for preparing the ABO3 type transition metal oxide composite rare earth tantalate ceramic coating having both infrared radiation shielding and high emissivity is specifically completed in the following steps:

[0055] 1. Pretreatment of substrate:

[0056] Removing impurities and oil stains on the substrate surface and roughening the substrate surface to obtain a pretreated substrate;

[0057] 2. Preparation of bonding layer:

[0058] The pretreated substrate is subjected to high-temperature heat treatment, and then an atmospheric plasma spraying process is used to prepare an adhesive layer on the surface of the heat-treated substrate to obtain a substrate with an adhesive layer attached thereto;

[0059] 3. Granulation treatment:

[0060] Mixed powder III is granulated to obtain an ABO3 transition metal oxide composite rare earth tantalate feed powder. This ABO3 transition metal oxide composite rare earth tantalate feed powder is then sprayed onto the surface of a substrate to which the adhesive layer is attached using an atmospheric plasma spraying process to obtain an ABO3 transition metal oxide composite rare earth tantalate coating having both infrared radiation shielding and high emissivity on the substrate surface. The remaining steps are the same as those in Specific Embodiments 1 to 8.

[0061] Specific embodiment ten: The difference between this embodiment and specific embodiments one to nine is that: the substrate described in step one is a metal substrate or a ceramic substrate; the metal substrate is a titanium aluminum alloy or a nickel-based alloy; the ceramic substrate is C / C, SiC / SiC, C / SiC or SiC / Si3N4; the method for removing impurities and oil stains on the surface of the substrate in step one is: first use 240#, 600#, 1000# sandpaper to polish the substrate to remove the oxide film, and then use a solvent to remove the oil stains on the surface of the substrate; the method for roughening the substrate surface in step one is: sandblasting or laser texturing; the parameters of the sandblasting are: the sand particle size is 1 0 to 15, the sandblasting pressure is 0.8 MPa to 1.1 MPa; the laser texturing parameters are: laser power of 8 kW to 10 kW, pulse frequency of 20 Hz to 40 Hz; the temperature of the high-temperature heat treatment of the pretreated substrate in step 2 is 1000 ± 100 ° C, and the time is 2 min to 5 min; the powder of the bonding layer is selected according to the type of substrate: when the substrate is a metal substrate, MCrAlY is selected as the bonding layer powder, wherein M is Ni, Co or NiCo; when the substrate is a ceramic substrate, RE-Si is selected as the bonding layer powder, wherein RE is a rare earth element, and the rare earth element is Hf or Y; the atmospheric plasma spraying process in step 2 is: the current is 450A~500A, the argon gas flow is 50slpm~55slpm, the hydrogen gas flow is 10slpm~15slpm, the carrier gas flow is 4slpm~6slpm, and the powder feeding disk speed is 40rpm~50rpm; the thickness of the adhesive layer attached to the surface of the substrate described in step 2 is 40μm~220μm; the process for granulating the mixed powder III described in step 3 is: the mixed powder III, phenylacetic acid, and polyvinyl alcohol are mixed in a mass ratio of (6~8):1:1, and then heated at a high temperature with a heat flow rate of 0.6m / s~0.8m / s and a temperature of 10 Granulation is performed at 0°C to 220°C and a spray pump pressure of 5MPa to 7MPa to obtain an ABO3 transition metal oxide composite rare earth tantalate feed powder. The atmospheric plasma spraying process parameters described in step 3 are: current of 550A to 750A, argon gas flow of 45slpm to 55slpm, hydrogen gas flow of 5slpm to 15slpm, carrier gas flow of 2slpm to 6slpm, and powder feed rate of 3rpm to 7rpm. The thickness of the ABO3 transition metal oxide composite rare earth tantalate coating on the substrate surface having both infrared radiation shielding and high emissivity in step 3 is 100μm to 400μm. The other steps are the same as those in specific embodiments 1 to 9.

[0062] The following examples are used to verify the beneficial effects of the present invention:

[0063] Example 1: A method for preparing an ABO3-type transition metal oxide composite rare earth tantalate ceramic (0.975GTO / 0.025GFO) having both infrared radiation shielding and high emissivity is specifically completed by the following steps:

[0064] 1. Weighing Gd2O3 and Fe2O3, mixing the weighed Gd2O3 and Fe2O3 uniformly to obtain mixed powder I, and calcining the mixed powder I to obtain ABO3 type transition metal oxide powder (GdFeO3);

[0065] The molar ratio of Gd2O3 to Fe2O3 in step 1 is 1:1;

[0066] The mixing method described in step 1 is as follows: weighing Gd2O3 and Fe2O3 and calcining them at 900°C for 6 hours, cooling them to room temperature, and obtaining Gd2O3 and Fe2O3 from which impurities and bound water have been removed; placing the Gd2O3 and Fe2O3 from which impurities and bound water have been removed, anhydrous ethanol, and zirconia grinding balls into a ball mill, and then ball milling them at a speed of 450 r / min for 12 hours, drying them at 100°C for 10 hours, grinding them for 2 hours, and passing them through a 200-mesh sieve to obtain mixed powder I; the mass ratio of the total mass of the Gd2O3 and Fe2O3 from which impurities and bound water have been removed in step 1 to anhydrous ethanol and zirconia microspheres is 1:0.2:4; the diameters of the zirconia microspheres are 1 mm and 3 mm, and they are mixed in a mass ratio of 1:1;

[0067] The calcination process in step 1 is as follows: heating to 1300°C at a heating rate of 5°C / min, calcining at 1300°C for 4 hours, and then cooling to room temperature in the furnace;

[0068] 2. Weighing Gd2O3 and Ta2O5, mixing the weighed Gd2O3 and Ta2O5 uniformly to obtain mixed powder II, and calcining the mixed powder II to obtain rare earth tantalate-based ceramic powder (Gd3TaO7);

[0069] The molar ratio of Gd2O3 and Ta2O5 described in step 2 is 3:1;

[0070] The mixing method described in step 2 is as follows: weighing Gd2O3 and Ta2O5 and calcining them at 900°C for 6 hours, cooling them to room temperature, and obtaining Gd2O3 and Ta2O5 from which impurities and bound water have been removed; placing the Gd2O3 and Ta2O5 from which impurities and bound water have been removed, anhydrous ethanol, and zirconia grinding balls into a ball mill, and then ball milling them at a speed of 450 r / min for 12 hours, drying them at 100°C for 10 hours, grinding them for 2 hours, and passing them through a 200-mesh sieve to obtain mixed powder II; the mass ratio of the total mass of the Gd2O3 and Ta2O5 from which impurities and bound water have been removed in step 2 to the mass ratio of anhydrous ethanol and zirconia microspheres is 1:0.2:4; the diameters of the zirconia microspheres are 1 mm and 3 mm, and they are mixed in a mass ratio of 1:1;

[0071] The calcination process in step 2 is as follows: heating to 1450°C at a heating rate of 5°C / min, calcining at 1450°C for 6 hours, and then cooling to room temperature in the furnace;

[0072] 3. Weighing ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder, and uniformly mixing the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder to obtain mixed powder III; pre-pressing, cold isostatically pressing, and calcining the mixed powder III to obtain an ABO3 transition metal oxide composite rare earth tantalate ceramic (0.975GTO / 0.025GFO) (X=0.025) with both infrared radiation shielding and high emissivity;

[0073] The molar ratio of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder in step 3 is 0.975:0.025;

[0074] The mixing method described in step three is: placing ABO3 type transition metal oxide powder, rare earth tantalate-based ceramic powder, anhydrous ethanol and zirconia grinding balls into a ball mill, then ball milling at a speed of 500 r / min for 15 hours, then drying at 100°C for 15 hours, grinding, and passing through a 400-mesh sieve to obtain mixed powder III; the mass ratio of the total mass of the ABO3 type transition metal oxide powder and the rare earth tantalate-based ceramic powder, anhydrous ethanol, and zirconia microspheres described in step three is 1:0.15:5; the diameters of the zirconia microspheres are 1 mm and 3 mm, and they are mixed in a mass ratio of 1:1; the pre-pressing molding described in step three is: using a press to pre-press the mixed powder III into a columnar block with a pressure of 12 MPa and a holding time of 5 minutes; the cold isostatic pressing pressure in step three is 250 MPa, and the holding time is 5 minutes;

[0075] The calcination process described in step 3 is: heating to 1550°C at a heating rate of 5°C / min, calcining at 1550°C for 10 hours, and then cooling to room temperature in the furnace.

[0076] Example 2: This example differs from Example 1 in that the molar ratio of the ABO3 transition metal oxide powder to the rare earth tantalate-based ceramic powder in Step 3 is 0.95:0.05, resulting in a product designated as 0.95GTO / 0.05GFO (X = 0.05). All other steps and parameters are the same as in Example 1.

[0077] Example 3: This example differs from Example 1 in that the molar ratio of the ABO3 transition metal oxide powder to the rare earth tantalate-based ceramic powder in Step 3 is 0.975:0.025, resulting in a product designated as 0.925GTO / 0.075GFO (X = 0.075). All other steps and parameters are the same as in Example 1.

[0078] Example 4: This example differs from Example 1 in that the molar ratio of the ABO3 transition metal oxide powder to the rare earth tantalate-based ceramic powder in Step 3 is 0.9:0.1, resulting in a product designated as 0.9GTO / 0.1GFO (X = 0.1). All other steps and parameters are the same as in Example 1.

[0079] Comparative Example 1: A method for preparing a rare earth tantalate (Gd3TaO7) ceramic block is specifically completed by the following steps:

[0080] 1. Weighing Gd2O3 and Ta2O5, mixing the weighed Gd2O3 and Ta2O5 uniformly to obtain a mixed powder, and calcining the mixed powder to obtain a rare earth tantalate-based ceramic powder (Gd3TaO7);

[0081] The molar ratio of Gd2O3 and Ta2O5 described in step 1 is 3:1;

[0082] The mixing method described in step 1 is as follows: weighing Gd2O3 and Ta2O5 and calcining them at 900°C for 6 hours, cooling them to room temperature, and obtaining Gd2O3 and Ta2O5 from which impurities and bound water have been removed; placing the Gd2O3 and Ta2O5 from which impurities and bound water have been removed, anhydrous ethanol, and zirconia grinding balls into a ball mill, and then ball milling them at a speed of 450 r / min for 12 hours, drying them at 100°C for 10 hours, grinding them for 2 hours, and passing them through a 200-mesh sieve to obtain a mixed powder; the mass ratio of the total mass of the Gd2O3 and Ta2O5 from which impurities and bound water have been removed in step 2 to anhydrous ethanol and zirconia microspheres is 1:0.2:4; the diameters of the zirconia microspheres are 1 mm and 3 mm, and they are mixed in a mass ratio of 1:1;

[0083] The calcination process in step 1 is as follows: heating to 1450°C at a heating rate of 5°C / min, calcining at 1450°C for 6 hours, and then cooling to room temperature in the furnace;

[0084] 2. Pre-pressing, cold isostatically pressing, and calcining the rare earth tantalate-based ceramic powder (Gd3TaO7) to obtain a rare earth tantalate (Gd3TaO7) ceramic block, denoted as X=0;

[0085] The pre-pressing molding in step 2 is as follows: using a press to pre-press the mixed powder III into a columnar block, the pressure is 12 MPa, and the holding time is 5 minutes; the cold isostatic pressing pressure in step 3 is 250 MPa, and the holding time is 5 minutes;

[0086] The calcination process in step 2 is as follows: heating to 1650° C. at a heating rate of 5° C. / min, calcining at 1650° C. for 10 h, and then cooling to room temperature in the furnace.

[0087] The ceramic samples prepared in Examples 1 to 4 and Comparative Example 1 were cut into the required sizes according to the test requirements. The phases of the samples were analyzed by X-ray diffractometer (XRD), and the 2θ range was 10° to 90°. The test results are as follows: Figure 1 The surface morphology of the sample was observed by scanning electron microscope (SEM), and the test results were shown as follows. Figure 2 The linear-hemispherical transmittance of the sample at 400nm to 2500nm was measured using a UV-visible-near-infrared spectrometer. The test results are shown in Figure 3 As shown. Using the spectral integrating sphere reflectance method, with gold as the reference sample and the light incident angle of 0°, the sample spectral emissivity is measured. The test results are shown as follows Figure 4 The thermal conductivity of the sample was measured using an LFA457 laser thermal conductivity meter at 20°C to 1200°C, with the interval between room temperature and 1200°C being 200°C. The test results are shown in the figure below. Figure 5 shown.

[0088] Figure 1 X-ray diffraction patterns of the ABO3-type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 and the Gd3TaO7 ceramic block prepared in Comparative Example 1;

[0089] The 0.975GTO / 0.025GFO (X=0.025), 0.95GTO / 0.05GFO (X=0.05), 0.925GTO / 0.075GFO (X=0.075), and 0.9GTO / 0.1GFO (X=0.1) materials prepared in Examples 1 to 4, respectively, showed no obvious impurity peaks. Comparison with the standard card revealed that the composite materials were composed of GdFeO3 with a perovskite structure and Gd3TaO7 with a Weberian structure. Comparison with the standard card revealed that the GTO material (X=0) prepared in Comparative Example 1 was composed of Gd3TaO7 with a Weberian structure.

[0090] Figure 2 Scanning electron microscope (SEM) morphologies and corresponding macroscopic morphologies of the surfaces of the ABO3-type transition metal oxide composite rare earth tantalate ceramic with both infrared radiation shielding and high emissivity prepared in Example 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1, with (a) showing Example 4 and (b) showing Example 1.

[0091] from Figure 2 From the SEM surface morphology and macroscopic morphology in (a) and (b), it can be seen that the composite material prepared in Example 4 has a good surface condition, no obvious cracks, and high density. GdFeO3 is dispersed in Gd3TaO7 as a second phase with a size of 1000-1500nm. The GTO material prepared in Comparative Example 1, i.e. Figure 2 As shown in (b), the sample is dense, without cracks and impurities.

[0092] Figure 3 The linear-hemispherical transmittance from 400 nm to 2500 nm of the ABO3-type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1;

[0093] from Figure 3 The infrared transmittance test chart shows that the composite materials prepared in Examples 1-4 have extremely low transmittance, with transmittances of less than 0.2% in the 400-2500nm wavelength range. Furthermore, the infrared transmittance of the materials decreases with increasing GFO content. The infrared transmittance of the GTO material prepared in Comparative Example 1 increases significantly with increasing wavelength, reaching a peak transmittance of nearly 80% in the 800-2500nm wavelength range.

[0094] Figure 4 Spectral emissivity from 2.5 μm to 14 μm of the ABO3 type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1;

[0095] from Figure 4 The infrared emissivity test graph shows that the composite materials prepared in Examples 1-4 each have high infrared emissivity. This further increases with increasing GFO content, demonstrating that GFO's intrinsic high absorption properties significantly impact the composite's infrared transmittance. The GTO material prepared in Comparative Example 1 exhibits low infrared emissivity in the 400-2000 nm range, particularly in the low-infrared band of 2.5 μm-6 μm. This demonstrates GTO's inherent low absorption properties.

[0096] Figure 5 Thermal conductivity of the ABO3-type transition metal oxide composite rare earth tantalate ceramics with both infrared radiation shielding and high emissivity prepared in Examples 1 to 4 of the present invention and the Gd3TaO7 ceramic block prepared in Comparative Example 1 at 50°C, 200°C, 400°C, 600°C, 800°C, 1000°C, and 1200°C;

[0097] from Figure 5 The thermal conductivity test graph shows that the composite materials prepared in Examples 1-4 significantly mitigate the upward trend in high-temperature thermal conductivity compared to the GTO material prepared in Comparative Example 1. The total thermal conductivity of the GTO material at high temperatures significantly increases with increasing temperature, indicating high radiative thermal conductivity due to thermal radiation transmission. The composite materials prepared in Examples 1 and 2 exhibit moderate resistance to radiation penetration; the composite material in Example 3 demonstrates excellent resistance to radiation penetration; and the composite material in Example 4 exhibits extremely strong resistance to radiation penetration, significantly reducing the upward trend in the thermal conductivity curve at high temperatures.

Claims

1. An ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating with both infrared radiation shielding and high emissivity, characterized in that The ABO3-type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity comprises an ABO3-type transition metal oxide with intrinsic high absorption characteristics dispersed in the rare earth tantalate ceramic matrix. The ABO3-type transition metal oxide is stacked in a lamellar structure to form a nearly spherical structure with a diameter of 1000-1500 nm. The ABO3-type transition metal oxide and the rare earth tantalate ceramic matrix belong to different crystal systems, and there is no infinite solid solution effect between the two. The rare earth tantalate ceramic matrix phase is Re3TaO7 with a Weber structure, wherein the Re element is Eu, Gd, Tb, Dy or Y; the ABO3 type transition metal oxide has an AFeO3 structure, and has the characteristics of Fe ion valence change and narrow band gap; wherein the A element is Eu, Gd, Tb, Dy or Y; the A element is the same as the Re element in Re3TaO7.

2. The ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 1, characterized in that The mass fraction of the ABO3 type transition metal oxide in the ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity is 0.89% to 3.8%.

3. The ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 1, characterized in that The ABO3-type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity has an ultra-low infrared transmittance of ≤0.2% in the 400-2500nm band, an average emissivity of >0.9 in the 2.5-14μm infrared band, an average emissivity of greater than 0.8 in the 2.5-6μm near-infrared band, and an average emissivity of >0.95 in the 6-14μm mid-infrared band.

4. The ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 1, characterized in that The thermal expansion coefficient of the ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating with both infrared radiation shielding and high emissivity within the range of 50-1400°C is 9.6×10 -6 K -1 ~9.8×10 -6 K -1 , and has a high matching performance with the metal matrix.

5. The method for preparing an ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 1, characterized in that The preparation method of the ABO3 type transition metal oxide composite rare earth tantalate ceramic having both infrared radiation shielding and high emissivity is specifically completed by the following steps:

1. Weighing B2O3 and A2O3, mixing the weighed B2O3 and A2O3 uniformly to obtain mixed powder I, and calcining the mixed powder I to obtain ABO3 type transition metal oxide powder; The A element in the A2O3 in step 1 is Eu, Gd, Tb, Dy or Y; the B element in the B2O3 is Fe; the molar ratio of A2O3 to B2O3 in step 1 is 1:1; The calcination process in step 1 is as follows: heating to 1200°C~1300°C at a heating rate of 3°C / min~5°C / min, calcining at 1200°C~1300°C for 4h~6h, and then cooling to room temperature with the furnace; 2. Weighing Re2O3 and Ta2O5, mixing the weighed Re2O3 and Ta2O5 uniformly to obtain mixed powder II, and calcining the mixed powder II to obtain rare earth tantalate-based ceramic powder; The molar ratio of Re2O3 and Ta2O5 described in step 2 is 3:1; The Re element in the Re2O3 in step 2 is Eu, Gd, Tb, Dy or Y; The calcination process in step 2 is as follows: heating to 1400°C~1500°C at a heating rate of 3°C / min~5°C / min, calcining at 1400°C~1500°C for 4h~7h, and then cooling to room temperature with the furnace; 3. Weighing ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder, and uniformly mixing the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder to obtain mixed powder III; pre-pressing, cold isostatically pressing, and calcining the mixed powder III to obtain ABO3 transition metal oxide composite rare earth tantalate ceramic with both infrared radiation shielding and high emissivity; The molar ratio of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder described in step 3 is (0.9-0.975):(0.025-0.1); The calcination process described in step three is: heating to 1550°C~1600°C at a heating rate of 3°C / min~5°C / min, calcining at 1550°C~1600°C for 8h~10h, and then cooling to room temperature with the furnace.

6. The method for preparing an ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 5, characterized in that The mixing method described in step 1 is as follows: the weighed B2O3 and A2O3 are calcined at 600℃~900℃ for 3h~6h respectively, and cooled to room temperature with the furnace to obtain B2O3 and A2O3 with impurities and bound water removed; the B2O3, A2O3 with impurities and bound water removed, anhydrous ethanol and zirconium oxide grinding balls are placed in a ball mill, and then ball milled at a speed of 300~500r / min for 12h~24h, and then dried at 80℃~100℃ for 8h~12h, ground, and sieved through a 200-mesh~400-mesh sieve to obtain a mixed powder I; the total mass of the B2O3 and A2O3 with impurities and bound water removed described in step 1 is the same as that of the B2O3 and A2O3 without impurities and bound water. The mass ratio of water ethanol and zirconium oxide microspheres is 1: (0.1-0.2): (4-6); the diameter of the zirconium oxide microspheres is 1 mm-3 mm; the mixing method described in step 2 is: weighing Re2O3 and Ta2O5 and calcining them at 600-900°C for 3-6 hours, cooling them to room temperature with the furnace to obtain Re2O3 and Ta2O5 with impurities and bound water removed; putting the Re2O3, Ta2O5 with impurities and bound water removed, anhydrous ethanol and zirconium oxide grinding balls into a ball mill, and then ball milling them at a speed of 300-500 r / min for 12-24 hours, and then drying them at 80-100°C for 8-12 hours. 2h, grind, pass through a 200-400 mesh sieve to obtain mixed powder II; the mass ratio of the total mass of Re2O3 and Ta2O5 from which impurities and bound water are removed in step 2 to anhydrous ethanol and zirconia microspheres is 1:(0.1-0.2):(4-6); the diameter of the zirconia microspheres is 1-3mm; the mixing method described in step 3 is: put ABO3 type transition metal oxide powder, rare earth tantalate-based ceramic powder, anhydrous ethanol and zirconia grinding balls into a ball mill, then ball mill at a speed of 300-500r / min for 10h-15h, and then dry at 60℃-100℃ for 10h-15h, grind Grind and pass through a 300-400 mesh sieve to obtain a mixed powder III; the mass ratio of the total mass of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder, anhydrous ethanol, and zirconia microspheres described in step three is 1:(0.1-0.2):(4-6); the diameter of the zirconia microspheres is 1-3 mm; the pre-pressing molding described in step three is: using a press to pre-press the mixed powder III into a columnar block, the pressure is 10-12 MPa, and the holding time is 3 min-5 min; the pressure of the cold isostatic pressing described in step three is 200 MPa-250 MPa, and the holding time is 3 min-5 min.

7. The method for preparing an ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 5, characterized in that The method for preparing the ABO3 type transition metal oxide composite rare earth tantalate coating having both infrared radiation shielding and high emissivity is specifically completed by the following steps:

1. Pretreatment of substrate: Removing impurities and oil stains on the substrate surface and roughening the substrate surface to obtain a pretreated substrate; 2. Preparation of bonding layer: The pretreated substrate is subjected to high-temperature heat treatment, and then an atmospheric plasma spraying process is used to prepare an adhesive layer on the surface of the heat-treated substrate to obtain a substrate with an adhesive layer attached thereto; 3. Granulation treatment: The mixed powder III is granulated to obtain an ABO3 type transition metal oxide composite rare earth tantalate feed powder; the ABO3 type transition metal oxide composite rare earth tantalate feed powder is sprayed onto the surface of a substrate to which an adhesive layer is attached using an atmospheric plasma spraying process to obtain an ABO3 type transition metal oxide composite rare earth tantalate coating having both infrared radiation shielding and high emissivity on the surface of the substrate.

8. The method for preparing an ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 7, characterized in that The substrate described in step 1 is a metal substrate or a ceramic substrate; the metal substrate is a titanium aluminum alloy or a nickel-based alloy; the ceramic substrate is C / C, SiC / SiC, C / SiC or SiC / Si3N4; the method for removing impurities and oil stains on the surface of the substrate in step 1 is: first use 240#, 600#, 1000# sandpaper to polish the substrate to remove the oxide film, and then use a solvent to remove the oil stains on the surface of the substrate; the method for roughening the surface of the substrate in step 1 is: sandblasting or laser texturing; the parameters of the sandblasting are: sand particle size is 10~15, and the sandblasting pressure is 0.8MPa~1.1MPa; the parameters of the laser texturing are: laser power is 8kW ~10kW, pulse frequency is 20Hz~40Hz; the temperature of the high-temperature heat treatment of the pretreated substrate in step 2 is 1000±100℃, and the time is 2min~5min; the powder of the bonding layer is selected according to the type of substrate: when the substrate is a metal substrate, MCrAlY is selected as the bonding layer powder, wherein M is Ni, Co or NiCo; when the substrate is a ceramic substrate, RE-Si is selected as the bonding layer powder, wherein RE is a rare earth element, and the rare earth element is Hf or Y; the atmospheric plasma spraying process in step 2 is: current 450A~500A, argon gas flow 50slpm ~55slpm, the hydrogen flow is 10slpm~15slpm, the carrier gas flow is 4slpm~6slpm, and the powder feeding disk speed is 40rpm~50rpm; the thickness of the adhesive layer attached to the surface of the substrate described in step 2 is 40μm~220μm; the process for granulating the mixed powder III described in step 3 is: the mixed powder III, phenylacetic acid, and polyvinyl alcohol are mixed in a mass ratio of (6~8):1:1, and then heated at a high temperature with a heat flow rate of 0.6m / s~0.8m / s, a temperature of 100℃~220℃, and a spray pump pressure of 5MPa~7M Pa to obtain ABO3 type transition metal oxide composite rare earth tantalate feeding powder; the parameters of the atmospheric plasma spraying process described in step three are: current of 550A~750A, argon gas flow of 45slpm~55slpm, hydrogen gas flow of 5slpm~15slpm, carrier gas flow of 2slpm~6slpm, and powder feeding rate of 3rpm~7rpm; in step three, the thickness of the ABO3 type transition metal oxide composite rare earth tantalate coating on the surface of the substrate with both infrared radiation shielding and high emissivity is 100μm~400μm.

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