Pr6O11 core-shell structure ZrB2 / SiC composite powder, preparation method and application thereof, and thermal protection coating

Abstract

This invention provides a Pr6O 11 This invention relates to a core-shell structured ZrB2 / SiC composite powder, its preparation method and application, and a thermal protective coating, belonging to the field of anti-oxidation and corrosion-resistant coating technology. It also provides a Pr6O... 11 A core-shell structured ZrB2 / SiC composite powder, with ZrB2 / SiC powder as the core material and Pr6O as the outer shell. 11 The shell material is formed by coating rare earth Pr6O. 11 Modification of ZrB2 / SiC powder to form Pr6O 11 The core-shell structure can minimize the oxidation of ZrB2 / SiC powder during the spraying process, and also utilize Pr6O 11 The lower melting point allows for further filling of defects such as pores in the coating during the spraying process, improving the density of the coating and thus effectively enhancing the coating's ultra-high temperature oxidation and ablation resistance.

Description

Technical Field

[0001] This invention relates to the field of antioxidant and corrosion-resistant coating technology, and particularly to a Pr6O coating. 11 Core-shell structured ZrB2 / SiC composite powder, its preparation method and application, and thermal protective coating. Background Technology

[0002] As the flight speed of hypersonic vehicles continues to increase, the aerodynamic heating experienced by C / C structural components becomes more intense, making oxidation and ablation protection a key research challenge. ZrB2 / SiC coatings are currently the most promising material for C / C ablation protection. ZrB2 / SiC coatings have attracted widespread attention in the field of anti-oxidation and ablation coating research due to their advantages such as high melting point, good thermal stability, high melting point of oxidation products, and low oxygen diffusivity. However, traditional thermal spraying of ZrB2 / SiC coatings suffers from problems such as oxidation during spraying, low coating density, high porosity, and poor infrared radiation performance. Furthermore, its low high-temperature emissivity makes it difficult to effectively dissipate heat. During service, the coating rapidly accumulates a large amount of heat energy, rising to very high temperatures in a short time. This causes the SiO2 phase, which fills the oxide layer, to actively volatilize or even rapidly vaporize, leading to a decrease in anti-oxidation and ablation performance and eventual coating failure. Summary of the Invention

[0003] In view of this, the object of the present invention is to provide a Pr6O 11 Core-shell structured ZrB2 / SiC composite powder, its preparation method and application, and thermal protective coating. The Pr6O provided by this invention... 11 The core-shell structure of ZrB2 / SiC composite powder can effectively improve the ultra-high temperature oxidation and ablation resistance of coatings.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0005] This invention provides a Pr6O 11 A core-shell structured ZrB2 / SiC composite powder, with ZrB2 / SiC powder as the core material and Pr6O as the outer shell. 11 As the shell material, the ZrB2 / SiC powder and Pr6O 11 The molar ratio is 100:0 to 20 and the Pr6O 11 The molar amount is not 0, and the volume ratio of ZrB2 to SiC in the ZrB2 / SiC powder is 1.5 to 3:1.

[0006] Preferably, the ZrB2 / SiC powder and Pr6O 11 The molar ratio is 100:5 to 15.

[0007] Preferably, the ZrB2 / SiC powder and Pr6O 11The molar ratio is 100:10.

[0008] Preferably, the volume ratio of ZrB2 to SiC in the ZrB2 / SiC powder is 2:1.

[0009] The present invention also provides the Pr6O described in the above technical solution. 11 A method for preparing core-shell structured ZrB2 / SiC composite powder includes the following steps:

[0010] ZrB2 and SiC were wet ball-milled to obtain a slurry;

[0011] The slurry is granulated to obtain granules;

[0012] The granules are densified to obtain densified spheres;

[0013] The densified spheres, soluble Pr salt, and solvent are mixed and then subjected to solvent removal and sintering in sequence to obtain the Pr6O. 11 Core-shell structured ZrB2 / SiC composite powder.

[0014] Preferably, the particle size of the granules is 30–100 μm.

[0015] Preferably, the granulation is spray granulation, and the conditions for spray granulation include: inlet temperature of 150-200℃, outlet temperature of 100-150℃, feeding speed of 20-50 RPM, and nozzle rotation speed of 30-50 Hz.

[0016] Preferably, the densification treatment is plasma spheroidization, and the conditions for plasma spheroidization include: argon flow rate of 40-80 SCFH, hydrogen flow rate of 3-8 SCFH, processing chamber pressure of 20-30 PSI, and powder feeding rate of 3-8 RPM.

[0017] The present invention also provides the Pr6O described in the above technical solution. 11 The core-shell structured ZrB2 / SiC composite powder or the Pr6O prepared by the method described in the above technical solution 11 Application of core-shell structured ZrB2 / SiC composite powder in the field of thermal protective coatings.

[0018] The present invention also provides a heat-protective coating, utilizing the Pr6O described in the above technical solution. 11 The core-shell structured ZrB2 / SiC composite powder or the Pr6O prepared by the method described in the above technical solution 11 The core-shell structured ZrB2 / SiC composite powder was prepared by atmospheric plasma spraying.

[0019] This invention provides a Pr6O 11A core-shell structured ZrB2 / SiC composite powder, with ZrB2 / SiC powder as the core material and Pr6O as the outer shell. 11 As the shell material, the ZrB2 / SiC powder and Pr6O 11 The molar ratio is 100:0 to 20 and the Pr6O 11 The molar amount is not 0, and the volume ratio of ZrB2 to SiC in the ZrB2 / SiC powder is 1.5 to 3:1.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention utilizes rare earth Pr6O coating 11 Modification of ZrB2 / SiC powder to form Pr6O 11 The core-shell structure can minimize the oxidation of ZrB2 / SiC powder during the spraying process, and also utilize Pr6O 11 The lower melting point (2042℃) allows for further filling of defects such as pores in the coating during the spraying process, improving the coating's density and thus effectively enhancing its ultra-high temperature oxidation and ablation resistance; simultaneously, Pr6O 11 It exhibits high emissivity in the 3–6 μm short-wavelength band by introducing Pr6O 11 It can improve the infrared emissivity of the coating in the 3-6μm short-wave band, increase the amount of heat radiated by the coating to the external environment per unit time under ultra-high temperature conditions, and thus improve the coating's ultra-high temperature thermal protection capability.

[0022] The present invention also provides the Pr6O described in the above technical solution. 11 The preparation method of the core-shell structured ZrB2 / SiC composite powder of the present invention is simple and easy to implement for industrial production. Attached Figure Description

[0023] Figure 1 The images show the SEM and EDS spectra of the ZSP10 cross section, where (a) to (b) are SEM spectra at different magnifications, (c) is the EDS spectrum, and (d) is the elemental spectrum of Pr, O, Zr, B and Si.

[0024] Figure 2 SEM and EDS spectra of the thermal protective coating;

[0025] Figure 3 The images show the cross-sectional microstructures of the coatings formed by ZSP5, ZSP10, ZSP15 and ZSP20, where (a) is the coating formed by ZSP5, (b) is the coating formed by ZSP10, (c) is the coating formed by ZSP15 and (d) is the coating formed by ZSP20.

[0026] Figure 4 Porosity curves of coatings formed for ZSP5, ZSP10, ZSP15 and ZSP20;

[0027] Figure 5 Pr6O 11 Emissivity curves of ZrB2 and SiC monocomponents;

[0028] Figure 6 The spectral emissivity curves of the coatings formed by ZSP5, ZSP10, ZSP15 and ZSP20 in the 3-20 μm and 3-6 μm bands are shown, where (a) is 3-20 μm and (b) is 3-6 μm.

[0029] Figure 7 The cross-sectional microstructure and elemental composition of ZrB2 / SiC powder are shown, where (a) is the microstructure of the cross-section of ZrB2 / SiC spheroidized powder, (b) is the EDS elemental surface distribution result, (c) is the microstructure diagram of the selected area, and (d) is the EDS point analysis result.

[0030] Figure 8 The microstructure of the cross section of the thermal protective coating prepared by ZSP0 at different magnifications;

[0031] Figure 9 The porosity curves of the coatings formed with ZSP0, ZSP5, ZSP10, ZSP15 and ZSP20 are shown.

[0032] Figure 10 XRD results for coatings formed with ZSP0, ZSP5, ZSP10, ZSP15 and ZSP20;

[0033] Figure 11 The spectral emissivity curves of coatings formed with ZSP0, ZSP5, ZSP10, ZSP15 and ZSP20 in the 3-20 μm and 3-6 μm bands are shown, where (a) is 3-20 μm and (b) is 3-6 μm. Detailed Implementation

[0034] This invention provides a Pr6O 11 A core-shell structured ZrB2 / SiC composite powder, with ZrB2 / SiC powder as the core material and Pr6O as the outer shell. 11 As the shell material, the ZrB2 / SiC powder and Pr6O 11 The molar ratio is 100:0 to 20 and the Pr6O 11 The molar amount is not 0, and the volume ratio of ZrB2 to SiC in the ZrB2 / SiC powder is 1.5 to 3:1.

[0035] In this invention, the ZrB2 / SiC powder and Pr6O11 The preferred molar ratio is 100:5 to 15, more preferably 100:10. In this invention, the molar amount of the ZrB2 / SiC powder refers to the average molar amount of the ZrB2 / SiC powder.

[0036] In this invention, the volume ratio of ZrB2 to SiC in the ZrB2 / SiC powder is preferably 2:1.

[0037] The present invention also provides the Pr6O described in the above technical solution. 11 A method for preparing core-shell structured ZrB2 / SiC composite powder includes the following steps:

[0038] ZrB2 and SiC were wet ball-milled to obtain a slurry;

[0039] The slurry is granulated to obtain granules;

[0040] The granules are densified to obtain densified spheres;

[0041] The densified spheres, soluble Pr salt, and solvent are mixed and then subjected to solvent removal and sintering in sequence to obtain the Pr6O11 core-shell structure ZrB2 / SiC composite powder.

[0042] Unless otherwise specified, all raw materials used in this invention are commercially available products in the field.

[0043] This invention involves wet ball milling ZrB2 and SiC to obtain a slurry.

[0044] In this invention, the wet ball milling process preferably further includes the addition of a binder, which is preferably PVA.

[0045] In this invention, the medium for wet ball milling is preferably water.

[0046] In this invention, ZrB2, SiC, deionized water and binder PVA are preferably added to a stirred ball mill and mixed to obtain the slurry.

[0047] In this invention, the sum of the solid content of ZrB2 and SiC in the slurry is preferably 30-50%, more preferably 35%, the solid content of the binder is preferably 0.2-1%, more preferably 0.4%, and the proportion of deionized water is preferably 50-70 wt%, more preferably 40 wt%.

[0048] In this invention, the grinding balls used in the wet ball milling are preferably zirconia grinding balls. The zirconia grinding balls preferably include zirconia balls with a diameter of 8 mm, zirconia balls with a diameter of 5 mm, and zirconia balls with a diameter of 2 mm. The mass ratio of the zirconia balls with a diameter of 8 mm, the zirconia balls with a diameter of 5 mm, and the zirconia balls with a diameter of 2 mm is preferably 1 to 2.1: 1.5 to 2.1: 1, and more preferably 1: 2: 1.

[0049] In this invention, the ball-to-material ratio of the wet ball mill is preferably 8:4.5 to 5.5, and more preferably 8:5.

[0050] In this invention, the rotational speed of the wet ball mill is preferably 300-500 r / min, more preferably 350 r / min; the time is preferably 1-3 h, more preferably 2.5 h.

[0051] After obtaining the slurry, a portion of it is granulated to obtain granules.

[0052] In this invention, the particle size of the granules is preferably 30 to 100 μm.

[0053] In this invention, the granulation is preferably spray granulation, and the spray granulation conditions preferably include: an inlet temperature of 150-200°C, an outlet temperature of 100-150°C, a feeding speed of 20-50 RPM, and a nozzle rotation speed of 30-50 Hz. The outlet temperature is more preferably 130°C, the feeding speed is more preferably 40 RPM, and the nozzle rotation speed is more preferably 40 Hz. To prevent powder sedimentation and accumulation, the slurry is continuously stirred with a glass rod during the spray granulation process.

[0054] After obtaining the granules, the present invention performs a densification treatment on the granules to obtain densified spheres.

[0055] After obtaining the slurry, the present invention preferably dries the slurry before performing the densification treatment.

[0056] In this invention, the drying is preferably carried out in a drying oven, the drying temperature is preferably 75-90°C, more preferably 80°C, and the drying time is preferably 24-72 hours, more preferably 48 hours.

[0057] In this invention, the densification treatment is preferably plasma spheroidization, and the plasma spheroidization conditions preferably include: an argon flow rate of 40-80 SCFH, a hydrogen flow rate of 3-8 SCFH, a processing chamber pressure of 20-30 PSI, and a powder feeding rate of 3-8 RPM. More preferably, the argon flow rate is 50 SCFH, the hydrogen flow rate is 5 SCFH, the processing chamber pressure is 15 PSI, and the powder feeding rate is 5 RPM.

[0058] After obtaining the densified spheres, the present invention mixes the densified spheres, soluble Pr salt, and solvent, and then sequentially removes the solvent and sinters to obtain the Pr6O. 11 Core-shell structured ZrB2 / SiC composite powder.

[0059] This invention employs a chemical infiltration method to process the densified spheres with Pr6O. 11 To cover.

[0060] In this invention, the soluble Pr salt is preferably Pr(NO3)3.

[0061] In this invention, the solvent is preferably an organic solvent, and the organic solvent is preferably anhydrous ethanol.

[0062] In this invention, the soluble Pr salt is first dissolved in a solvent, and the soluble Pr salt is accelerated to dissolve by a magnetic stirrer. Then, the densified spheres are added, and magnetic stirring is continued (preferably for 6 hours) to obtain a mixture.

[0063] In this invention, the solvent removal method is preferably heating, which is preferably carried out in a forced-air drying oven. The heating temperature is preferably 50-80°C, more preferably 70°C, and the heating time is preferably 6-12 hours.

[0064] In this invention, the sintering is preferably carried out in an air-heated furnace.

[0065] In this invention, the sintering temperature is preferably 400–600°C, more preferably 500°C, and the holding time is preferably 10 hours. During the sintering process, the soluble Pr salt on the powder surface is fully oxidized to Pr6O. 11 And completely remove any residual solvent from the powder.

[0066] In this invention, the heating rate from room temperature to the sintering temperature is preferably 5 to 10 °C / min.

[0067] After sintering, the present invention preferably crushes and sieves the obtained sintered granules sequentially to obtain the Pr6O. 11 Core-shell structured ZrB2 / SiC composite powder.

[0068] In this invention, the crushing is preferably grinding; the sieving is preferably done using a 10 or 90 μm sieve to remove large polymer particles and fine broken particles, to obtain the Pr6O. 11 Core-shell structured ZrB2 / SiC composite powder.

[0069] The present invention also provides the Pr6O described in the above technical solution. 11The core-shell structured ZrB2 / SiC composite powder or the Pr6O prepared by the method described in the above technical solution 11 Application of core-shell structured ZrB2 / SiC composite powder in the field of thermal protective coatings.

[0070] The present invention does not impose any special limitation on the specific method of application, and any method known to those skilled in the art can be used.

[0071] The present invention also provides a heat-protective coating, utilizing the Pr6O described in the above technical solution. 11 The core-shell structured ZrB2 / SiC composite powder or the Pr6O prepared by the method described in the above technical solution 11 The core-shell structured ZrB2 / SiC composite powder was prepared by atmospheric plasma spraying.

[0072] In this invention, the current for atmospheric plasma spraying is preferably 700-900A, more preferably 800A; the main gas is preferably 50-90 LPM; the auxiliary gas is preferably 30-60 LPM, more preferably 50 LPM; the carrier gas is preferably 5-15 LPM, more preferably 10 LPM; the powder feed rate is preferably 1-3 RPM, more preferably 2 RPM; and the spraying distance is preferably 50-80 cm, more preferably 65 cm.

[0073] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0074] Example 1

[0075] (1) Slurry preparation using ball milling process. ZrB2 and SiC raw material powders were added to a stirred ball mill and mixed with deionized water and binder PVA. The volume ratio of ZrB2 and SiC raw material powders was 2:1. The solid content of ZrB2 and SiC raw material powders in the ball milled slurry was 35%, the solid content of binder PVA was 0.4%, the proportion of deionized water was 64.6 wt%, and the grinding balls were zirconia grinding balls (including zirconia balls with a diameter of 8 mm, zirconia balls with a diameter of 5 mm and zirconia balls with a diameter of 2 mm, and the mass ratio of 8 mm, 5 mm and 2 mm zirconia balls was 1:2:1). The ball-to-material ratio was 8:5, the ball milling speed was 350 r / min, and the time was 2.5 h.

[0076] (2) Agglomerated ZrB2 / SiC powder was prepared using spray granulation technology. During spray granulation, the slurry was continuously stirred with a glass rod. The inlet temperature of spray granulation was 200℃, the outlet temperature was 130℃, the feeding speed was 40RPM, and the nozzle rotation speed was 40Hz.

[0077] (3) The obtained slurry is dried. This is done in a drying oven at 80℃ for 48 hours.

[0078] (4) The agglomerated powder obtained by spray granulation was densified using plasma spheroidization technology. The Ar gas flow rate was 50 SCFH, the H2 gas flow rate was 5 SCFH, the processing chamber pressure was 15 PSI, and the powder feeding rate was 5 RPM;

[0079] (5) Pr6O was applied to the plasma-spheroidized ZrB2 / SiC powder using a chemical infiltration method. 11 Coating. First, Pr(NO3)3 was added to anhydrous ethanol, and the Pr(NO3)3 particles were dissolved using a magnetic stirrer to accelerate the process. The anhydrous ethanol volume was 1200 mL. The average molar mass percentage of Pr(NO3)3 relative to the spheroidized ZrB2 / SiC powder was set to 0 mol%, 5 mol%, 10 mol%, 15 mol%, and 20 mol% (resulting in Pr6O). 11 The core-shell structured ZrB2 / SiC composite powders were designated ZSP0, ZSP5, ZSP10, ZSP15, and ZSP20, respectively. After the particles were completely dissolved, the spheroidized powder was slowly added to a praseodymium nitrate-alcohol solution, and the magnetic stirring speed was increased to stir the mixture for 6 hours. After stirring, the mixture was transferred to a forced-air drying oven to remove the alcohol solvent at 70°C for 12 hours. The powder was then dispersed into multiple crucibles and transferred to an air-heated furnace at room temperature, heated to 600°C at a rate of 5°C / min, and held for 10 hours to fully oxidize the Pr(NO3)3·6H2O on the powder surface to Pr6O. 11 The residual alcohol in the powder was completely removed. The heated powder exhibited some sintering; therefore, it was crushed and ground using a mortar and pestle, and then sieved through 10 and 90 μm sieves to remove large polymer particles and fine broken particles, yielding Pr6O. 11 Core-shell structured ZrB2 / SiC composite powder.

[0080] Thermal protective coatings were prepared using atmospheric plasma spraying technology. The current was 800A, the main gas was 90 LPM, the auxiliary gas was 50 LPM, the carrier gas was 10 LPM, the powder feed rate was 2 RPM, and the spraying distance was 65 cm.

[0081] Figure 1 The images show the SEM and EDS spectra of the ZSP10 cross section. Figure 1(a)–(b) are SEM spectra at different magnifications, (c) is the EDS spectrum, and (d) is the elemental spectrum of Pr, O, Zr, B, and Si. The results show that Pr6O 11 It was successfully introduced into ZrB2 / SiC powder and successfully formed Pr6O. 11 Core-shell structure.

[0082] Figure 2 The SEM and EDS spectra of the heat-protective coating show that Pr6O 11 It was successfully introduced into ZrB2 / SiC powder and successfully formed Pr6O. 11 Core-shell structure.

[0083] Figure 3 Microscopic morphology images of the cross-sections of coatings formed from ZSP5, ZSP10, ZSP15, and ZSP20. Figure 3 In the image (a) showing the coating formed by ZSP5, (b) showing the coating formed by ZSP10, (c) showing the coating formed by ZSP15, and (d) showing the coating formed by ZSP20, it can be seen that Pr6O 11 The core-shell structured ZrB2 / SiC composite powder is distributed in strips inside the coating.

[0084] Figure 4 The porosity curves of the coatings formed for ZSP5, ZSP10, ZSP15, and ZSP20 show that, with the increase of Pr6O... 11 As the content increases, the density of the coating continuously increases, while the porosity continuously decreases.

[0085] Figure 5 Pr6O 11 Emissivity curves of ZrB2 and SiC monocomponents Figure 6 The spectral emissivity curves of the coatings formed from ZSP5, ZSP10, ZSP15, and ZSP20 in the 3–20 μm and 3–6 μm wavelength bands are shown. Figure 6 In (a) the micrometers range from 3 to 20 μm, and in (b) they range from 3 to 6 μm. This shows that Pr6O... 11 The emissivity of ZrB2 in the 3–6 μm short-wavelength band is significantly higher than that of ZrB2. After introducing ZrB2 into the coating, the emissivity of the coating is significantly improved, with the ZSP10 coating showing the greatest increase in emissivity, reaching 0.94%.

[0086] Figure 7 The cross-sectional microstructure and elemental composition of ZrB2 / SiC powder are shown. Figure 7 (a) shows the microstructure of the cross-section of ZrB2 / SiC spheroidized powder, (b) shows the EDS elemental distribution results, (c) shows the microstructure of the selected region, and (d) shows the EDS point analysis results. Figure 8The microstructure of the cross section of the thermal protective coating prepared by ZSP0 at different magnifications; Figure 9 The porosity curves for coatings formed with ZSP0, ZSP5, ZSP10, ZSP15, and ZSP20 are shown above. From the results, it can be seen that without the use of Pr6O... 11 The modified ZrB2-SiC powder did not form a core-shell structure. The coating applied with it was loose overall. The porosity of the coating was measured to be 19.91%, which was significantly higher than that of the four experimental groups.

[0087] Figure 10 The XRD results of the coatings formed with ZSP0, ZSP5, ZSP10, ZSP15 and ZSP20 show that Pr6O 11 The core-shell structure effectively avoids oxidation problems during the coating spraying process.

[0088] Figure 11 The spectral emissivity curves of coatings formed with ZSP0, ZSP5, ZSP10, ZSP15, and ZSP20 in the 3–20 μm and 3–6 μm wavelength bands are shown. Figure 11 In (a) the micrometers range from 3 to 20 μm, and in (b) they range from 3 to 6 μm. It can be seen that the addition of Pr6O... 11 After modification, the emissivity of ZSP5 and ZSP10 in the 3-6 μm short-wavelength band is significantly higher than that of the unmodified ZSP0 coating.

[0089] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A Pr6O 11 The core-shell structured ZrB2 / SiC composite powder is characterized by, Using ZrB2 / SiC powder as the core material and Pr6O as the core material 11 As the shell material, the ZrB2 / SiC powder and Pr6O 11 The molar ratio is 100:5~15.

2. The Pr6O according to claim 1 11 The core-shell structured ZrB2 / SiC composite powder is characterized by, The ZrB2 / SiC powder and Pr6O 11 The molar ratio is 100:

10.

3. The Pr6O according to claim 1 11 The core-shell structured ZrB2 / SiC composite powder is characterized by, The volume ratio of ZrB2 to SiC in the ZrB2 / SiC powder is 2:

1.

4. The Pr6O according to any one of claims 1 to 3 11 The method for preparing core-shell structured ZrB2 / SiC composite powder is characterized by, Includes the following steps: ZrB2 and SiC were wet ball-milled to obtain a slurry; The slurry is granulated to obtain granules; The granules are densified to obtain densified spheres; The densified spheres, soluble Pr salt, and solvent are mixed and then subjected to solvent removal and sintering in sequence to obtain the Pr6O. 11 Core-shell structured ZrB2 / SiC composite powder.

5. The preparation method according to claim 4, characterized in that, The particle size of the granules is 30~100μm.

6. The preparation method according to claim 4, characterized in that, The granulation is spray granulation, and the conditions for spray granulation include: inlet temperature of 150~200℃, outlet temperature of 100~150℃, feeding speed of 20~50RPM, and nozzle rotation speed of 30~50Hz.

7. The preparation method according to claim 4, characterized in that, The densification process is plasma spheroidization, and the conditions for plasma spheroidization include: argon flow rate of 40~80 SCFH, hydrogen flow rate of 3~8 SCFH, processing chamber pressure of 20~30 PSI, and powder feeding rate of 3~8 RPM.

8. The Pr6O according to any one of claims 1 to 3 11 The core-shell structured ZrB2 / SiC composite powder or Pr6O prepared by the method described in any one of claims 4 to 7 11 Application of core-shell structured ZrB2 / SiC composite powder in the field of thermal protective coatings.

9. A heat-protective coating, characterized in that, Using Pr6O as described in any one of claims 1 to 3 11 The core-shell structured ZrB2 / SiC composite powder or Pr6O prepared by the method described in any one of claims 4 to 7 11 The core-shell structured ZrB2 / SiC composite powder was prepared by atmospheric plasma spraying.

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