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

Abstract

The invention discloses ABO3 type transition 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 metal oxide composite rare earth tantalate ceramic / coating with infrared radiation shielding and high emissivity prepared by the invention is characterized in that ABO3 type transition metal oxide with intrinsic high absorption characteristics is dispersed and distributed in a rare earth tantalate ceramic base phase. The ABO3 type transition metal oxide composite tantalate ceramic with infrared radiation shielding and high emissivity and the coating prepared by the invention have ultra-low infrared transmittance (T is less than or equal to 0.2%) in a wavelength range of 400-2500nm, and have excellent infrared radiation shielding characteristic; the average emissivity gt of the infrared band (2.5-14 [mu] m); 0.9, 0.9; the heat conductivity upwarp trend at the high temperature (greater than or equal to 800 DEG C) is obviously inhibited, and the method has very important significance.

Description

Technical Field

[0001] The 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 are often used to protect hot-end components that are washed by high-temperature heat flow, such as the outer skin of ultra-high-speed aircraft, aircraft engines, and large gas turbine blades, so that the corresponding engineering systems can operate stably in high-temperature environments and improve their performance and work efficiency. Rare earth tantalates are very promising thermal barrier coating materials because of their low thermal conductivity, good phase stability and corrosion resistance, suitable thermal expansion coefficient, and good mechanical properties. However, similar to common TBC materials, they are translucent to infrared radiation in the short infrared band, which means that the thermal radiation generated by the external high-temperature heat flow can penetrate the coating and cause thermal damage to the substrate. In a heat flow environment of 2000K, the combined conduction-radiation heat flux of TBCs can be about 30% higher than the conduction heat flux alone. The problem of reduced thermal insulation capacity of TBCs caused by infrared radiation heat transfer cannot be ignored. Therefore, improving the radiation penetration resistance of TBC materials is a very urgent need for the new generation of ultra-high temperature gas turbine systems. However, the research on the regulation of the radiation penetration resistance of thermal barrier coating material systems is still in its infancy, and related research is very rare. In the past five years, only Chinese patents (CN 115233069 A) and (CN 115010492 A) have respectively disclosed a composite material with parallel arrangement and distribution of platinum micron sheets and a composite material with noble metal nanoparticles dispersed in a ceramic matrix and a preparation method thereof, which improve the infrared radiation shielding performance of ceramics. The selection of the second phase of the noble metal has problems such as high cost, failure of thermal expansion matching between the noble metal and the ceramic matrix, and increased thermal conductivity. Therefore, we continue to develop thermal barrier coating ceramic materials and coating preparation methods with low cost, high radiation penetration resistance, high thermal expansion coefficient, and low thermal conductivity integrated 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 of the infrared radiation shielding thermal barrier coating material prepared by the existing method is not low enough, the economic cost of the low infrared transmittance material composited with precious metal nanoparticles is high, 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. A method for preparing the thermal barrier coating is provided, which has both infrared radiation shielding and high emissivity and a method for preparing the same.

[0004] The invention discloses 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 having intrinsic high absorption characteristics is dispersed in the rare earth tantalate ceramic matrix phase. The ABO3 type transition metal oxide is stacked into a spherical approximation with a lamellar structure and has 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 in the following steps:

[0006] 1. Weigh B2O3 or BO and A2O3, mix the weighed B2O3 or BO and A2O3 evenly to obtain mixed powder I, and calcine 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 to 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 described in step 1 is: 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 with the furnace;

[0011] 2. Weigh Re2O3 and Ta2O5, mix the weighed Re2O3 and Ta2O5 evenly to obtain mixed powder II, and calcine the mixed powder II to obtain rare earth tantalate-based ceramic powder;

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

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

[0014] The calcination process described in step 2 is: 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 with the furnace;

[0015] 3. Weigh ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder, and mix the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder evenly to obtain mixed powder III; pre-press the mixed powder III, cold isostatically press, and calcine to obtain 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 in the following steps:

[0019] 1. Pretreatment of substrate:

[0020] Removing impurities and oil stains on the substrate surface, and then 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 a bonding layer on the surface of the heat-treated substrate to obtain a substrate with the bonding layer attached;

[0023] 3. Granulation treatment:

[0024] The mixed powder III is granulated to obtain 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 the substrate to which the adhesive layer is attached by 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 substrate surface.

[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 in a rare earth tantalate matrix, and utilizes the intrinsic high optical absorption characteristics of the ABO3 transition metal oxide and the enhanced particle back optical scattering caused by the proximity of the infrared wavelength to the particle size, so that 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 400-2500nm, and an average emissivity of more than 0.8 in the near infrared band (2.5-6μm), thereby improving the ability of the ceramic matrix phase to resist high temperature radiation penetration; and the difference in thermal expansion coefficient of the composite ceramic with that of the ceramic matrix phase is less than 0.5×10 -6 K -1 The high-temperature thermal conductivity is suppressed, ensuring the high-temperature stability of the thermal barrier coating, thereby increasing 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 the existing precious metal nanoparticle composite ceramic system and dispersed phase composite ceramic system, 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 having 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 The scanning electron microscope (SEM) morphology and corresponding macroscopic morphology of the surface 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, wherein (a) is Example 4 and (b) is Example 1;

[0031] Figure 3 The linear-hemispherical transmittance from 400nm to 2500nm 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 4The spectral emissivity from 2.5 μm to 14 μm of the ABO3 type transition metal oxide composite rare earth tantalate ceramics having 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 The 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 implementation method one: This implementation method 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 to form a spherical approximation 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 implementation method 2: The difference between this implementation method and specific implementation method 1 is that the A element in the ABO3 type transition metal oxide is Eu, Gd, Tb, Dy or Y; the B element is Cr, Fe, Co or Ni; the rare earth tantalate ceramic matrix is ​​Re3TaO7 with a Weber structure, wherein the Re element is Eu, Gd, Tb, Dy or Y; the Weber structure Re3TaO7 has higher mechanical properties and high temperature thermal expansion matching. The other steps are the same as those in specific implementation method 1.

[0036] Specific implementation method three: This implementation method is different from specific implementation method one or two in that: 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 bandgap; wherein the A element is Eu, Gd, Tb, Dy or Y; and the A element is the same as the Re element in Re3TaO7. The other steps are the same as those in specific implementation method one or two.

[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 having both infrared radiation shielding and high emissivity is 0.89% to 3.8%. The other steps are the same as those in specific embodiments 1 to 3.

[0038] Specific embodiment 5: This embodiment differs from specific embodiments 1 to 4 in that: the ABO3 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. The other steps are the same as those of specific embodiments 1 to 4.

[0039] Specific embodiment 6: The difference between this embodiment and specific embodiments 1 to 5 is 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 50-1400°C is 9.6×10 -6 K -1 ~9.8×10 -6 K -1 , and the metal matrix has a high matching property. 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. Weigh B2O3 or BO and A2O3, mix the weighed B2O3 or BO and A2O3 evenly to obtain mixed powder I, and calcine 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 to 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 described in step 1 is: 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 with the furnace;

[0046] 2. Weigh Re2O3 and Ta2O5, mix the weighed Re2O3 and Ta2O5 evenly to obtain mixed powder II, and calcine the mixed powder II to obtain rare earth tantalate-based ceramic powder;

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

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

[0049] The calcination process described in step 2 is: 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 with the furnace;

[0050] 3. Weigh ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder, and mix the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder evenly to obtain mixed powder III; pre-press the mixed powder III, cold isostatically press, and calcine to obtain 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 described in step 3 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. The other steps are the same as those of 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 calcined 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 a mixed powder I; step The mass ratio of the total mass of B2O3 or BO, A2O3 from which impurities and bound water are removed to anhydrous 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: calcining the weighed Re2O3 and Ta2O5 at 600°C-900°C for 3h-6h, cooling to room temperature with the furnace to obtain Re2O3 and Ta2O5 from which impurities and bound water are removed; placing the Re2O3, Ta2O5, anhydrous ethanol and zirconium oxide grinding balls from which impurities and bound water are removed into a ball mill, and then ball milling at a speed of 300-500 r / min for 12h- 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 the mass ratio of anhydrous ethanol and zirconium oxide microspheres is 1:(0.1~0.2):(4~6); the diameter of the zirconium oxide 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 zirconium oxide grinding balls into a ball mill, and then ball mill at a speed of 300~500r / min for 10h~15h, and then at 60℃~100℃ Dry for 10h to 15h, grind, and pass through a 300-mesh to 400-mesh sieve to obtain a mixed powder III; the total mass ratio 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 1-3mm; 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 10-12MPa, and the holding time is 3min-5min; the cold isostatic pressing pressure described in step 3 is 200MPa-250MPa, and the holding time is 3min-5min. The other steps are the same as the 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 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 then 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 a bonding layer on the surface of the heat-treated substrate to obtain a substrate with the bonding layer attached;

[0059] 3. Granulation treatment:

[0060] The mixed powder III is granulated to obtain ABO3 transition metal oxide composite rare earth tantalate feed powder; the ABO3 transition metal oxide composite rare earth tantalate feed powder is sprayed onto the surface of the substrate to which the adhesive layer is attached by 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 other steps are the same as those in the first to eighth embodiments.

[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 grind 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 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 is 8 kW to 10 kW, and the pulse frequency is 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 plate 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 uniformly in a mass ratio of (6~8): 1:1, and then at a high temperature heat flow rate of 0.6m / s~0.8m / s and a temperature of 10 Granulation is carried out under the conditions of 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 parameters of the atmospheric plasma spraying process described in step 3 are: current is 550A to 750A, argon gas flow is 45slpm to 55slpm, hydrogen gas flow is 5slpm to 15slpm, carrier gas flow is 2slpm to 6slpm, and powder feeding rate is 3rpm to 7rpm; the thickness of the ABO3 transition metal oxide composite rare earth tantalate coating with both infrared radiation shielding and high emissivity on the surface of the substrate in step 3 is 100μm to 400μm. The other steps are the same as those in specific embodiments one to nine.

[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, which 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, calcining the mixed powder I to obtain ABO3 type transition metal oxide powder (GdFeO3);

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

[0066] The mixing method described in step 1 is: calcining the weighed Gd2O3 and Fe2O3 at 900°C for 6h, cooling to room temperature with the furnace to obtain Gd2O3 and Fe2O3 with impurities and bound water removed; putting the Gd2O3 and Fe2O3 with impurities and bound water removed, anhydrous ethanol and zirconium oxide grinding balls into a ball mill, then ball milling at a speed of 450r / min for 12h, then drying at 100°C for 10h, grinding for 2h, and passing through a 200-mesh sieve to obtain mixed powder I; the total mass ratio of the Gd2O3 and Fe2O3 with impurities and bound water removed in step 1 to anhydrous ethanol and zirconium oxide microspheres is 1:0.2:4; the diameters of the zirconium oxide microspheres are 1mm and 3mm, and they are mixed in a mass ratio of 1:1;

[0067] The calcination process described in step 1 is: 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. Weigh Gd2O3 and Ta2O5, mix the weighed Gd2O3 and Ta2O5 evenly to obtain mixed powder II, and calcine 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: calcining the weighed Gd2O3 and Ta2O5 at 900°C for 6h, cooling to room temperature with the furnace to obtain Gd2O3 and Ta2O5 with impurities and bound water removed; putting the Gd2O3 and Ta2O5 with impurities and bound water removed, anhydrous ethanol and zirconium oxide grinding balls into a ball mill, then ball milling at a speed of 450r / min for 12h, then drying at 100°C for 10h, grinding for 2h, and passing through a 200-mesh sieve to obtain mixed powder II; the total mass ratio of the Gd2O3 and Ta2O5 with impurities and bound water removed in step 2 to anhydrous ethanol and zirconium oxide microspheres is 1:0.2:4; the diameters of the zirconium oxide microspheres are 1mm and 3mm, and they are mixed in a mass ratio of 1:1;

[0071] The calcination process described in step 2 is: 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 mixing the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder evenly to obtain mixed powder III; pre-pressing, cold isostatic pressing, and calcining the mixed powder III to obtain 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: put ABO3 transition metal oxide powder, rare earth tantalate-based ceramic powder, anhydrous ethanol and zirconium oxide grinding balls into a ball mill, then ball mill at a speed of 500r / min for 15h, and then dry at 100°C for 15h, grind, and pass through a 400-mesh sieve to obtain mixed powder III; 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 three are in a mass ratio of 1:0.15:5; the diameters of the zirconium oxide microspheres are 1mm and 3mm, and they are mixed in a mass ratio of 1:1; the pre-pressing molding described in step three is: use a press to pre-press the mixed powder III into a columnar block, the pressure is 12MPa, and the holding time is 5min; the cold isostatic pressing pressure described in step three is 250MPa, and the holding time is 5min;

[0075] The calcination process described in step three 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: The difference between this example and Example 1 is that the molar ratio of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder in step 3 is 0.95:0.05, and the obtained product is recorded as 0.95GTO / 0.05GFO (X=0.05). The other steps and parameters are the same as those in Example 1.

[0077] Example 3: The difference between this example and Example 1 is that 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, and the obtained product is recorded as 0.925GTO / 0.075GFO (X=0.075). The other steps and parameters are the same as those in Example 1.

[0078] Example 4: The difference between this example and Example 1 is that the molar ratio of the ABO3 transition metal oxide powder and the rare earth tantalate-based ceramic powder in step 3 is 0.9:0.1, and the obtained product is recorded as 0.9GTO / 0.1GFO (X=0.1). The other steps and parameters are the same as those 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. Weigh Gd2O3 and Ta2O5, mix the weighed Gd2O3 and Ta2O5 evenly to obtain a mixed powder, and calcine 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: calcining the weighed Gd2O3 and Ta2O5 at 900°C for 6h, cooling to room temperature with the furnace to obtain Gd2O3 and Ta2O5 with impurities and bound water removed; putting the Gd2O3 and Ta2O5 with impurities and bound water removed, anhydrous ethanol and zirconium oxide grinding balls into a ball mill, then ball milling at a speed of 450r / min for 12h, then drying at 100°C for 10h, grinding for 2h, and passing through a 200-mesh sieve to obtain a mixed powder; the total mass ratio of the Gd2O3 and Ta2O5 with impurities and bound water removed in step 2 to anhydrous ethanol and zirconium oxide microspheres is 1:0.2:4; the diameters of the zirconium oxide microspheres are 1mm and 3mm, and they are mixed in a mass ratio of 1:1;

[0083] The calcination process described in step 1 is: 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 isostatic 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 described in step 2 is: using a press machine to pre-press the mixed powder III into a columnar block, the pressure is 12MPa, and the holding time is 5min; the cold isostatic pressing pressure described in step 3 is 250MPa, and the holding time is 5min;

[0086] The calcination process described in step 2 is: heating to 1650° C. at a heating rate of 5° C. / min, calcining at 1650° C. for 10 hours, 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 microscopy (SEM), and the test results are shown in Figure 2 The linear-hemispherical transmittance of the sample at 400nm to 2500nm was measured using a UV-Vis-NIR spectrometer. The test results are shown in Figure 3 As shown. Using the spectral integrating sphere reflection 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 in Figure 4 The thermal conductivity of the sample was measured using an LFA457 laser thermal conductivity meter at 20°C to 1200°C, where the interval from room temperature to 1200°C was 200°C. The test results are shown in Figure 5 shown.

[0088] Figure 1 X-ray diffraction patterns of the ABO3 type transition metal oxide composite rare earth tantalate ceramics having 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 have no obvious impurity peaks. Compared with the standard card, it is found that the composite material is composed of GdFeO3 with a perovskite structure and Gd3TaO7 with a Weber structure. The GTO material (X=0) prepared in Comparative Example 1 is compared with the standard card and is composed of Gd3TaO7 with a Weber structure.

[0090] Figure 2 The scanning electron microscope (SEM) morphology and corresponding macroscopic morphology of the surface 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, wherein (a) is Example 4 and (b) is Example 1;

[0091] from Figure 2 It can be seen from the SEM surface morphology and macroscopic morphology in (a) and (b) 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 400nm to 2500nm 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 It can be seen from the infrared transmittance test graph that the composite materials prepared in Examples 1 to 4 have extremely low transmittance, with a transmittance of <0.2% in the wavelength range of 400 to 2500 nm, and with the increase of the GFO content, the infrared transmittance of the material shows a downward trend. The infrared transmittance of the GTO material prepared in Comparative Example 1 increases significantly with the increase of wavelength, and the highest transmittance is close to 80% in the wavelength range of 800 nm to 2500 nm.

[0094] Figure 4 The spectral emissivity from 2.5 μm to 14 μm of the ABO3 type transition metal oxide composite rare earth tantalate ceramics having 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 It can be seen from the infrared emissivity test graph that the composite materials prepared in Examples 1 to 4 have a high infrared emissivity. As the content of GFO increases, the infrared emissivity of the material is further improved, which confirms that the intrinsic high absorption characteristics of GFO have a very positive effect on the reduction of the infrared transmittance of the composite material. The GTO material prepared in Comparative Example 1 has a low infrared emissivity in the range of 400 to 2000nm, especially in the low infrared band of 2.5μm-6μm. This reflects the intrinsic low absorption characteristics of GTO.

[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 It can be seen from the thermal conductivity test graph that the composite materials prepared in Examples 1 to 4 respectively have greatly alleviated the rising trend of high-temperature thermal conductivity compared with the GTO material prepared in Comparative Example 1. The total thermal conductivity of the GTO material at high temperature rises significantly with the increase of temperature, indicating that the radiation thermal conductivity brought by thermal radiation penetration is very high. Among them, the composite materials prepared in Examples 1 and 2 have a certain ability to resist radiation penetration; the composite material of Example 3 shows excellent ability to resist radiation penetration; the composite material of Example 4 shows extremely strong ability to resist radiation penetration, which significantly improves the high-temperature upward trend of the thermal conductivity curve.

Claims

1. An ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity, characterized in that The ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating with both infrared radiation shielding and high emissivity is an ABO3 type transition metal oxide with intrinsic high absorption characteristics dispersed in the rare earth tantalate ceramic matrix phase, and the ABO3 type transition metal oxide is stacked in a lamellar structure to form a spherical approximation 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.

2. The ABO3 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 A element in the ABO3 type transition metal oxide is Eu, Gd, Tb, Dy or Y; the B element is Cr, Fe, Co or Ni; the rare earth tantalate ceramic base phase is Re3TaO7 with a Weber structure, wherein the Re element is Eu, Gd, Tb, Dy or Y; the Re3TaO7 with a Weber structure has higher mechanical properties and high-temperature thermal expansion matching.

3. The ABO3 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 rare earth tantalate ceramic base 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 bandgap width; wherein the A element is Eu, Gd, Tb, Dy or Y; the A element is the same as the Re element in Re3TaO7.

4. The ABO3 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%.

5. The ABO3 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.

6. The ABO3 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 transition metal oxide composite rare earth tantalate ceramic / coating having 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 matching performance with the metal matrix.

7. The method for preparing the ABO3 type transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity as claimed in claim 1, characterized 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:

1. Weigh B2O3 or BO and A2O3, mix the weighed B2O3 or BO and A2O3 evenly to obtain mixed powder I, and calcine the mixed powder I to obtain ABO3 type transition metal oxide powder; 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; The molar ratio of A2O3 and B2O3 described in step 1 is 1:1; The molar ratio of A2O3 and BO described in step 1 is 1:2; The calcination process described in step 1 is: 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 with the furnace; 2. Weigh Re2O3 and Ta2O5, mix the weighed Re2O3 and Ta2O5 evenly to obtain mixed powder II, and calcine the mixed powder II to obtain rare earth tantalate-based ceramic powder; The molar ratio of Re2O3 to Ta2O5 described in step 2 is 3:1; The Re element in the Re2O3 described in step 2 is Eu, Gd, Tb, Dy or Y; The calcination process described in step 2 is: 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 with the furnace; 3. Weigh ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder, and mix the weighed ABO3 transition metal oxide powder and rare earth tantalate-based ceramic powder evenly to obtain mixed powder III; pre-press the mixed powder III, cold isostatically press, and calcine 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 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.

8. The method for preparing the ABO3 type transition metal oxide composite rare earth tantalate ceramic with both infrared radiation shielding and high emissivity according to claim 7, characterized in that The mixing method described in step 1 is: weighing B2O3 or BO, A2O3 and calcining them at 600°C to 900°C for 3h to 6h, cooling them to room temperature, and obtaining B2O3 or BO, A2O3 from which impurities and bound water are removed; placing B2O3 or BO, A2O3 from which impurities and bound water are removed, anhydrous ethanol and zirconium oxide grinding balls into a ball mill, and then ball milling them at a speed of 300 to 500 r / min for 12h to 24h, and then drying them at 80°C to 100°C for 8h to 12h, grinding them, and passing them through a 200-mesh to 400-mesh sieve to obtain a mixed powder I; the B2O3 or BO, A2O3 from which impurities and bound water are removed described in step 1 is The mass ratio of the total mass of Re2O3 to anhydrous 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: the weighed Re2O3 and Ta2O5 are calcined at 600°C-900°C for 3h-6h, and then cooled to room temperature with the furnace to obtain Re2O3 and Ta2O5 with impurities and bound water removed; the Re2O3, Ta2O5, anhydrous ethanol and zirconium oxide grinding balls with impurities and bound water removed are placed in a ball mill, and then ball milled at a speed of 300-500r / min for 12h-24h, and then at 80°C-100°C. Dry for 8h to 12h, grind, and pass 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 zirconium oxide microspheres is 1:(0.1-0.2):(4-6); the diameter of the zirconium oxide 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 zirconium oxide 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-15 h, grind, and pass through a 300-mesh to 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 three 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 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.

9. The method for preparing the ABO3 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 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:

1. Pretreatment of substrate: Removing impurities and oil stains on the substrate surface, and then 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 a bonding layer on the surface of the heat-treated substrate to obtain a substrate with the bonding layer attached; 3. Granulation treatment: The mixed powder III is granulated to obtain 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 the substrate to which the adhesive layer is attached by 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 substrate surface.

10. The method for preparing the ABO3 transition metal oxide composite rare earth tantalate ceramic / coating having both infrared radiation shielding and high emissivity according to claim 9, 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 grind 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: the sand particle size is 10 to 15, and the sandblasting pressure is 0.8MPa to 1.1MP a; the laser texturing parameters are: laser power of 8kW to 10kW, pulse frequency of 20Hz to 40Hz; the temperature of the high temperature heat treatment of the pretreated substrate in step 2 is 1000±100℃, and the time is 2min to 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 The current is 450A to 500A, the argon gas flow is 50slpm to 55slpm, the hydrogen gas flow is 10slpm to 15slpm, the carrier gas flow is 4slpm to 6slpm, and the powder feeding plate speed is 40rpm to 50rpm; the thickness of the adhesive layer attached to the surface of the substrate described in step 2 is 40μm to 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 uniformly in a mass ratio of (6 to 8): 1:1, and then heated to a high temperature with a heat flow rate of 0.6m / s to 0.8m / s and a temperature of 100℃ to 220℃. , granulation under the condition of a spray pump pressure of 5MPa to 7MPa to obtain an 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 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 feeding rate of 3rpm to 7rpm; in step three, the thickness of the ABO3 type transition metal oxide composite rare earth tantalate coating with both infrared radiation shielding and high emissivity on the surface of the substrate is 100μm to 400μm.

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