High-temperature-resistant ceramic powder for plasma spraying as well as preparation method and application of high-temperature-resistant ceramic powder
By combining zirconium diboride, silicon carbide, molybdenum silicide, and hafnium boride, ceramic powder was prepared using plasma spraying technology. This solved the oxidation problem of Cf/SiC composite materials at high temperatures, forming a dense, antioxidant coating that improved the ablation resistance and stability of the material.
Patent Information
- Application Number
- CN202511045384.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-11-18
AI Technical Summary
Cf/SiC composites are prone to oxidation at high temperatures, especially the oxidation of the reinforcing carbon fiber, which leads to a decline in performance. Furthermore, the existing ceramic working layer has problems such as high porosity and microcracks, which affect the oxidation resistance and ablation resistance.
Zirconium diboride and silicon carbide are used as the main materials, and molybdenum disilicide and hafnium boride are used as auxiliary materials. A dense working layer is prepared by plasma spraying technology. The interaction and dual properties of each component are utilized to improve the oxidation resistance, and the coating performance is optimized by controlling the spraying parameters.
It significantly improves the oxidation and ablation resistance of Cf/SiC composite materials, effectively protecting them in ultra-high temperature environments above 1800℃. The ablation time is increased to 81.5s, the average ablation rate is reduced to 0.036mm/s, and the coating has high density and good bonding strength.
Smart Images
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Abstract
Description
Technical Field
[0001] This application relates to the technical field of ceramic powders, and in particular to a high-temperature resistant ceramic powder for plasma spraying, its preparation method, and its application. Background Technology
[0002] Due to its excellent properties such as low density, good initial strength, high specific strength, high temperature resistance, and thermal shock resistance, Cf / SiC (carbon fiber / silicon carbide) composites have become a key focus in the research and development of structural materials for supersonic aircraft. Although they possess many superior properties, the issue of "easy oxidation" has always been a key focus and challenge in Cf / SiC composite research. In Cf / SiC composites, the matrix SiC oxidizes at high temperatures to form silicon oxide, creating a dense film covering the surface of the matrix silicon carbide, preventing further intrusion by oxidizing media and thus giving the matrix good oxidation resistance. However, the reinforcing carbon fiber phase in the composite is extremely prone to oxidation in high-temperature oxidizing environments. Once the fibers oxidize, their performance deteriorates sharply, ultimately causing the composite to lose its good mechanical properties. As a thermal structural material, Cf / SiC composite components not only need to transmit complex structural loads at high temperatures but also withstand complex thermomechanical impact loads and oxidative erosion. Therefore, improving the oxidation and ablation resistance of Cf / SiC composites is a crucial prerequisite for ensuring their normal service.
[0003] Preparing an antioxidant working layer on the surface of materials is a widely used method for antioxidant properties in composite materials. Borides, as ceramic materials with high temperature resistance and ablation resistance, have better chemical stability. Compared with other high temperature and ablation resistant ceramic materials, borides also have high electrical conductivity, high thermal conductivity, and good corrosion resistance. Currently, the antioxidant working layer used in carbon fiber reinforced silicon carbide matrix composites is mainly a ceramic zirconium diboride (ZrB2) based working layer. ZrB2 has excellent properties such as high melting point (3245℃), high strength, and low saturated vapor pressure. In a high-temperature oxygen environment, the B2O3 generated by the oxidation of ZrB2 has fluidity and can effectively seal cracks and pores in the working layer and the matrix, thereby achieving the purpose of antioxidant properties. However, ceramic working layers have a larger porosity and more microcracks than metal working layers. The presence of pores and microcracks in the working layer weakens its antioxidant effect, thus greatly reducing its ablation resistance. Summary of the Invention
[0004] To address the aforementioned technical problems, this application provides a high-temperature resistant ceramic powder for plasma spraying, its preparation method, and its application.
[0005] In a first aspect, this application provides a high-temperature resistant ceramic powder for plasma spraying, comprising a main material and auxiliary materials in a weight ratio of 100:(18-32), wherein the main material comprises zirconium diboride and silicon carbide, and the auxiliary material comprises molybdenum disilicide, and the particle size of zirconium diboride, silicon carbide and molybdenum disilicide is <100μm.
[0006] Preferably, the weight ratio of the main material to the auxiliary material is 100:25.
[0007] Preferably, the excipients further include hafnium boride with a particle size of <100μm.
[0008] Preferably, the weight ratio of molybdenum disilicide to hafnium boride is 20:5.
[0009] By adopting the above technical solution, this application uses zirconium diboride and silicon carbide as the main materials of ceramic powder for high-temperature plasma spraying, and molybdenum disilicide and hafnium boride as auxiliary materials. After compounding, a ceramic powder for high-temperature plasma spraying is obtained. After spraying, a dense working layer can be formed, thereby playing a good protective role for Cf / SiC composite materials.
[0010] Specifically, zirconium diboride, as a good refractory material, and silicon carbide, as a high-temperature structural material, both have thermal expansion coefficients that are close to those of SiC. Therefore, they have good compatibility with Cf / SiC composite materials. In addition, the oxidation products of zirconium diboride and silicon carbide interact to generate a high-temperature glassy protective phase and a high-temperature antioxidant crystalline phase, which allows the working layer to be tightly bonded to the Cf / SiC composite material and has good stability and oxidation resistance. However, its stability in ultra-high temperature (below 1800℃) is not good. Therefore, this application also adds molybdenum disilicide and hafnium boride as auxiliary materials. Molybdenum disilicide has dual characteristics of metal and ceramic, with high melting point, low density and excellent high-temperature oxidation resistance. Its addition to the system can inhibit crack propagation in the working layer and improve oxidation resistance. Hafnium boride also has dual characteristics of ceramic and metal, high melting point and high hardness. It will cause crack deflection and crack termination in the working layer, effectively inhibiting and preventing crack propagation and effectively improving the oxidation resistance of the working layer. Experimental data show that the high-temperature plasma spraying ceramic powder of this application enables Cf / SiC composite materials to have superior oxidation and ablation resistance, with a high ablation time (up to 81.5s) and a low average ablation rate (down to 0.036mm / s), meeting the requirements for use in high-temperature and ultra-high-temperature strong oxidation applications, and can successfully pass ultra-high temperature laser burn-through tests above 1800℃.
[0011] This application strictly controls the weight ratio of main materials and auxiliary materials, as well as the weight ratio of molybdenum disilicide and hafnium boride, further improving the ablation resistance time of Cf / SiC composite materials and reducing the average ablation rate. Specifically, too low a molybdenum disilicide content leads to a smaller binder phase in the system, resulting in increased porosity of the working layer, thereby increasing the residual stress of the working layer and reducing the bonding strength of the ceramic composite working layer. Too high a content leads to an excessive binder phase, causing particle accumulation, which also increases the porosity of the working layer, reduces the bonding strength, and increases the roughness of the working layer, resulting in lower flatness and poorer surface bonding strength. In laser ablation, weak bonding leads to increased laser absorption of the working layer, thereby reducing the laser ablation resistance of the working layer. Low hafnium boride addition leads to increased porosity, but if the addition is too high, it will repel zirconium disilicide, increasing the roughness of the working layer and affecting its appearance.
[0012] Secondly, this application provides a method for preparing the above-mentioned high-temperature resistant ceramic powder for plasma spraying, comprising the following steps: mixing the main material, auxiliary material and lubricant, ball milling, then mixing with binder, dispersant and water for spray granulation, heat treatment, sieving, to obtain high-temperature resistant ceramic powder for plasma spraying with a particle size distribution of 25-58μm.
[0013] By adopting the above technical solution, this application involves blending the main material, auxiliary material, and lubricant, ball milling to ensure thorough mixing of all raw materials, then adding the binder, dispersant, and water for further blending. Following this, spray granulation is performed, controlling the feed rate of the constant flow pump, the inlet and outlet temperatures, and the nozzle rotation speed. Subsequently, heat treatment is carried out at 1600℃. Particles sintered at this temperature exhibit a certain strength, with a volume shrinkage of no more than 10% after sintering. After this series of treatments, a high-temperature plasma spray-resistant ceramic powder with good flowability, a dense surface, and certain mechanical strength is obtained. In the specific embodiments of this application, the lubricant is sodium dodecyl sulfate, the binder is PEG-800, and the dispersant is a 40wt% ammonium polyacrylate solution. Those skilled in the art can reasonably replace these components according to actual conditions, and this should not be used to limit the scope of protection of this application.
[0014] Thirdly, this application provides an application of the above-mentioned high-temperature resistant plasma spraying ceramic powder, including the following steps: S1, substrate pretreatment; S2, spraying a primer layer: using supersonic plasma spraying to spray a primer layer onto the surface of the pretreated substrate; S3, spraying a working layer: using supersonic plasma spraying to spray the high-temperature resistant plasma spraying ceramic powder onto the surface of the primer layer, wherein the voltage of the supersonic plasma spraying is 80-110V, the current is 380-440A, the main gas flow rate is 80-100L / min, the auxiliary gas flow rate is 45-55L / min, the carrier gas flow rate is 8-12L / min, the spraying distance is 100-130mm, and a working layer with a thickness of 350-360μm is obtained.
[0015] Preferably, in step S3, the voltage for supersonic plasma spraying is 90V.
[0016] Preferably, in step S3, the current for supersonic plasma spraying is 420A.
[0017] Preferably, in step S3, the main gas flow rate for supersonic plasma spraying is 80 L / min, the auxiliary gas flow rate is 50 L / min, and the carrier gas flow rate is 12 L / min.
[0018] Preferably, in step S3, the spraying distance of the supersonic plasma spraying is 100mm.
[0019] By adopting the above technical solution, this application first cleans the substrate (Cf / SiC composite material) with industrial alcohol, followed by sandblasting to change the distribution of residual stress on the substrate surface, thereby improving the activation of the cleaned substrate surface and greatly enhancing the bonding strength between the underlayer and the substrate. Next, this application utilizes supersonic plasma spraying technology to spray high-purity metallic silicon powder onto the pre-treated substrate surface to form an underlayer with a thickness of 25-30 μm. This underlayer acts as a transition between the working layer and the substrate, exhibiting good wettability and compatibility, increasing adhesion between the working layer and the substrate, and enabling partial contact between the working layer and the substrate. To leverage the high adhesion and compatibility of the working layer, this application utilizes supersonic plasma spraying. Compared to traditional spraying techniques such as ordinary supersonic plasma spraying and high-speed flame spraying, supersonic plasma spraying produces coatings with higher density, stronger interfacial bonding, lower porosity, and better fatigue resistance. This allows for the preparation of high-performance underlayers and working layers. Subsequently, this application continues to use supersonic plasma spraying to prepare the working layer. This spraying method significantly enhances its advantages in preparing ceramic coatings like the working layer, effectively blocking the erosion of high-temperature gases and corrosive media, slowing down the oxidation and corrosion of alloy components in ceramic coatings, and improving service life. After the above series of treatments, this application obtained a working layer with a thickness of 350-360 μm, achieving excellent ablation protection for Cf / SiC composite materials.
[0020] This application also controls a series of parameters in step S3. Through orthogonal experiments, the most suitable spraying parameters were obtained. The voltage of the supersonic plasma spraying was controlled at 90V, the current at 420A, the main gas flow rate at 80L / min, the auxiliary gas flow rate at 50L / min, the carrier gas flow rate at 12L / min, and the spraying distance at 100mm. These parameters together form a complete spraying scheme, which makes the working layer have the best appearance morphology (roughness of 3.076μm), the lowest porosity (as low as 0.62%), and the best ablation resistance, thus meeting the requirements of Cf / SiC composite materials in high-temperature and ultra-high-temperature strong oxidation applications.
[0021] In summary, this application has the following beneficial technical effects: 1. In this application, zirconium diboride and silicon carbide are used together as the main materials of ceramic powder for high-temperature plasma spraying, and molybdenum disilicide and hafnium boride are used as auxiliary materials. After compounding, a ceramic powder for high-temperature plasma spraying is obtained. This fully utilizes the good thermal properties of zirconium diboride and silicon carbide and their interaction. Furthermore, molybdenum disilicide has the dual characteristics of metal and ceramic, with high melting point, low density, and excellent high-temperature oxidation resistance. Adding it to the main material can inhibit crack propagation in the working layer and improve oxidation resistance. Hafnium boride also has the dual characteristics of ceramic and metal, high melting point, and high hardness. It can cause crack deflection and crack formation in the working layer. The termination phenomenon effectively inhibits and prevents crack propagation and improves the oxidation resistance of the working layer; 2. The preparation method of this application involves mixing the main material, auxiliary material and lubricant, ball milling to ensure that the raw materials are fully mixed, then adding the binder, dispersant and water for mixing, followed by spray granulation, controlling the feed rate of the constant flow pump, the inlet and outlet temperatures and the nozzle speed, and then heat treating at a temperature of 1600℃. The particles obtained by sintering at this temperature have a certain strength, and the volume shrinkage after sintering does not exceed 10%. After the above series of treatments, a high-temperature plasma spraying resistant ceramic powder with good fluidity, dense surface and certain mechanical strength is obtained. 3. The high-temperature plasma spraying ceramic powder of this application can be used to protect Cf / SiC composite materials, enabling Cf / SiC composite materials to have superior oxidation and ablation resistance properties. It can enable Cf / SiC composite materials to pass ultra-high temperature laser burn-through tests above 1800℃. By strictly controlling the spraying parameters, the ablation time can reach up to 81.5s, and the average ablation rate of the working layer is as low as 0.036mm / s. Attached Figure Description
[0022] Figure 1-1 These are microscopic images of the powder after sintering in Example 1 at 500X, 1000X, and 2000X magnification. Figure 1-2 These are microscopic images of the powder after sintering in Example 2 at 500X, 1000X, and 2000X magnification. Figure 1-3 These are microscopic images of the powder after sintering in Example 3 at 500X, 1000X, and 2000X magnification. Figure 1-4 These are microscopic images of the powder after sintering in Example 4 at 500X, 1000X, and 2000X magnification. Figure 1-5 These are microscopic images of the powder after sintering in Example 5 at 500X, 1000X, and 2000X. Figure 1-6 These are microscopic images of the powder after sintering in Example 6 at 500X, 1000X, and 2000X magnification. Figure 1-7These are microscopic images of the powder after sintering in Example 7 at 500X, 1000X, and 2000X magnification. Figure 1-8 These are microscopic images of the powder after sintering in Example 8 at 500X, 1000X, and 2000X. Figure 1-9 These are microscopic images of the powder after sintering in Example 9 at 500X, 1000X, and 2000X. Figure 2-1 For example 1.1, the working layer is shown in 200X and 500X micrographs; Figure 2-2 The working layer of Application Example 1.2 is shown in 200X and 500X micrographs. Figure 2-3 The working layer of application example 1.3 is shown in 200X and 500X microscopic morphology images; Figure 2-4 The working layer of Application Example 1.4 is shown in 200X and 500X micrographs. Figure 2-5 The working layer of Application Example 1.5 is shown in 200X and 500X micrographs. Figure 2-6 For example 1.6, the working layer is shown in 200X and 500X micrographs; Figure 2-7 The working layer of Application Example 1.7 is shown in 200X and 500X micrographs. Figure 2-8 The working layer of Application Example 1.8 is shown in 200X and 500X micrographs. Figure 2-9 The working layer of Application Example 1.9 is shown in 200X and 500X micrographs. Figure 3-1 Example 1.1 shows the ablation morphology of the working layer and local ablation diagram; Figure 3-2 Example 1.2 shows the ablation morphology of the working layer and local ablation diagrams; Figure 3-3 Example 1.3 shows the ablation morphology of the working layer and local ablation diagrams; Figure 3-4 Example 1.4 shows the ablation morphology of the working layer and local ablation diagrams; Figure 3-5 Example 1.5 shows the ablation morphology of the working layer and local ablation images; Figure 3-6 Example 1.6 shows the ablation morphology of the working layer and local ablation diagrams; Figure 3-7 Example 1.7 shows the ablation morphology of the working layer and local ablation diagrams; Figure 3-8 Example 1.8 shows the ablation morphology of the working layer and local ablation diagrams; Figure 3-9 Example 1.9 shows the ablation morphology of the working layer and local ablation diagrams; Figure 4-1 The porosity distribution diagram of the working layer in Application Example 1.1; Figure 4-2 The porosity distribution diagram of the working layer in Application Example 1.2; Figure 4-3 The porosity distribution diagram of the working layer in Application Example 1.3; Figure 4-4 The porosity distribution diagram of the working layer in Application Example 1.4; Figure 4-5 The porosity distribution diagram of the working layer in Application Example 1.5; Figure 4-6 Example 1.6 shows the porosity distribution of the working layer; Figure 4-7 The porosity distribution diagram of the working layer in Application Example 1.7; Figure 4-8 Example 1.8 shows the porosity distribution of the working layer; Figure 4-9 The porosity distribution diagram of the working layer in Application Example 1.9; Figure 4-10 The porosity distribution diagram of the working layer in Application Example 2.1; Figure 4-11 Example 2.2 shows the porosity distribution of the working layer; Figure 4-12 Example 2.3 shows the porosity distribution of the working layer; Figure 4-13 Example 2.4 shows the porosity distribution of the working layer; Figure 4-14 Example 2.5 shows the porosity distribution of the working layer; Figure 4-15 Example 2.6 shows the porosity distribution of the working layer; Figure 4-16 Example 2.7 shows the porosity distribution of the working layer; Figure 4-17 This is an application example 2.8, showing the porosity distribution of the working layer. Detailed Implementation
[0023] Material source Unless otherwise specified, all raw materials used in this application are commercially available products, specifically: Zirconium diboride, silicon carbide, molybdenum disilicide, hafnium boride, and yttrium oxide-stabilized zirconium oxide are all ultrafine powders with a particle size <100μm; the yttrium oxide-stabilized zirconium oxide has a yttrium oxide content of 13-14wt%. High-purity metallic silicon powder, particle size 45μm; Sodium dodecyl sulfate, CAS No. 151-21-3, effective content 99wt%; PEG-800, CAS No. 25322-68-3; Ammonium polyacrylate aqueous solution, concentration 40 wt%.
[0024] The present application will be further described in detail below with reference to embodiments and comparative examples.
[0025] The amount of sodium dodecyl sulfate lubricant used in this application is 1 wt% of the total amount of main and auxiliary materials, the amount of PEG-800 binder is 2 wt% of the total amount of main and auxiliary materials, the amount of ammonium polyacrylate aqueous solution dispersant is 6 wt% of the total amount of main and auxiliary materials, and the amount of water is 60 wt% of the total amount of main and auxiliary materials. The calculation is only explained in Example 1. The amount of each substance in the other examples is implemented according to the above addition ratio, and will not be repeated.
[0026] <Example 1> A method for preparing high-temperature resistant ceramic powder for plasma spraying includes the following steps: 750g of zirconium diboride, 250g of silicon carbide, 200g of molybdenum disilicide, 50g of hafnium boride, and 12.5g of sodium dodecyl sulfate lubricant are mixed and ball-milled in a ball mill for 4 hours. Then, 25g of binder PEG-800, 75g of dispersant ammonium polyacrylate aqueous solution, and 750g of water are introduced into the ball-milled material and stirred evenly to obtain a mixed slurry for spray granulation. Subsequently, the parameters of the constant flow pump of the granulator are adjusted to 80g / min, the inlet temperature is 250℃, the outlet temperature is 120℃, and the nozzle speed is 31Hz. After granulation, the powder is heat-treated at 1600℃ for 2 hours, cooled, and passed through a 250-mesh sieve and a 500-mesh sieve to obtain high-temperature resistant ceramic powder for plasma spraying with a particle size distribution of 25-58μm.
[0027] <Example 2-9> A method for preparing high-temperature resistant ceramic powder for plasma spraying differs from Example 1.1 in that the amounts of molybdenum disilicide and hafnium boride are different, as detailed in Table 1-1; otherwise, the method is the same as in Example 1.
[0028] Table 1-1 Material Usage (g) Group Zirconium diboride dosage Silicon carbide dosage Molybdenum disilicide dosage Hafnium boride dosage Example 1 750 250 200 50 Example 2 750 250 180 0 Example 3 750 250 180 50 Example 4 750 250 180 100 Example 5 750 250 200 0 Example 6 750 250 200 100 Example 7 750 250 220 0 Example 8 750 250 220 50 Example 9 750 250 220 100 Comparative Example 1.1 The difference from Example 1 is that 200g of molybdenum disilicide and 50g of hafnium boride are replaced with 187.5g of zirconium diboride and 62.5g of silicon carbide, while the rest are the same as in Example 1.
[0029] Comparative Example 1.2 The difference from Example 1 is that 200g of molybdenum disilicide is replaced with 200g of hafnium boride, while the rest is the same as in Example 1.
[0030] Comparative Example 1.3 The difference from Example 1 is that 50g of hafnium boride is replaced with 50g of molybdenum disilicide, while the rest is the same as in Example 1.
[0031] <Application Example 1.1> The application of a high-temperature resistant ceramic powder for plasma spraying includes the following steps: S1. Substrate pretreatment: Clean the substrate with dimensions of 30mm×30mm×5mm with industrial alcohol until there is no obvious oil residue on the substrate surface. Then, use a sandblasting machine to sandblast the substrate to improve the surface activation of the substrate. S2. Spraying the base coat: High-purity metallic silicon powder is sprayed onto the surface of the pretreated substrate using supersonic plasma spraying. The voltage of the supersonic plasma spraying is controlled at 100V, the current at 400A, the main gas flow rate at 90L / min, the auxiliary gas flow rate at 9L / min, the carrier gas flow rate at 8L / min, and the spraying distance at 125mm, resulting in a base coat with a thickness of 25-30μm. S3. Spraying the working layer: The high-temperature resistant plasma-sprayed ceramic powder obtained in Example 1 is sprayed onto the surface of the base layer using supersonic plasma spraying. The voltage of the supersonic plasma spraying is controlled at 90V, the current at 420A, the main gas flow rate at 80L / min, the auxiliary gas flow rate at 50L / min, the carrier gas flow rate at 12L / min, and the spraying distance at 100mm, resulting in a working layer with a thickness of 350-360μm.
[0032] <Application Example 1.2-1.9> The application of a high-temperature resistant ceramic powder for plasma spraying differs from Application Example 1.1 in that the high-temperature resistant ceramic powder for plasma spraying obtained in Example 1 in step S3 is replaced with the high-temperature resistant ceramic powder for plasma spraying obtained in Examples 2-9, while the rest is the same as Application Example 1.1.
[0033] <Comparative Application Examples 1-3> The difference from Application Example 1.1 is that the high-temperature resistant plasma spraying ceramic powder prepared in Example 1 in step S3 is completely replaced with the high-temperature resistant plasma spraying ceramic powder prepared in Comparative Examples 1.1-1.3, while the rest is the same as Application Example 1.1.
[0034] Performance testing 1. Morphological characterization: The powder obtained in the examples was scanned using a scanning electron microscope for surface observation, specifically as follows: Figures 1-1 to 1-9 As shown, the working layer obtained in use cases 1.1-1.9 is scanned for surface observation, specifically as follows: Figures 2-1 to 2-9 As shown; 2. Laser Ablation Performance Test: The samples obtained in Examples 1.1-1.9 were subjected to laser ablation. A CO2 laser was used, with a laser ablation power of 500W, a spot diameter of 2mm, and an Ar atmosphere. The ablation (burn-through) time (s) and the average ablation rate of the working layer (mm / s) were recorded. The ablation morphology and local ablation images from Examples 1.1-1.9 are shown below. Figures 3-1 to 3-9 As shown; 3. Working layer porosity test: The porosity of the working layer obtained in test cases 1.1-1.9 is measured using image analysis, and microscopic scanning images are taken, such as... Figures 4-1 to 4-9 As shown, the porosity (%) of the working layer cross section was identified and calculated using ImagePro-Plus software; 4. Working layer roughness test: The surface roughness of the working layer obtained in application examples 1.1-1.9 is tested using a contact roughness tester. Five points are measured and the average value is calculated.
[0035] Table 2.1 Data Record-1 Group Ablation time (s) Average ablation rate of the working layer (mm / s) Blank control (no coating) 8.00 / Application Example 1.1 81.50 0.036 Comparative Application Example 1 17.60 0.193 Comparative Application Example 2 29.93 0.096 Comparative Application Example 3 23.00 0.128 Table 2.2 Data Records-2 Data Analysis: As can be seen from Table 2.1, the ablation time of Application Example 1.1 of this application is 81.5s, and the average ablation rate of the working layer is 0.036mm / s. Compared with the blank control, the ablation time is increased by more than 10 times, which proves that the high-temperature plasma spraying ceramic powder of this application can indeed be used to protect Cf / SiC composite materials. It can give Cf / SiC composite materials excellent oxidation resistance and ablation resistance, with high ablation resistance time and low average ablation rate, which meets the requirements for use in high temperature and ultra-high temperature strong oxidation application fields, and can successfully pass the ultra-high temperature laser burn-through test above 1800℃.
[0036] Compared to Application Example 1.1, where the working layer is a zirconium diboride-silicon carbide working layer, the ablation time is 17.60 s and the average ablation rate is 0.193 mm / s. In Application Example 2, where the working layer is a zirconium diboride-silicon carbide-hafnium boride working layer, the ablation time is 29.93 s and the average ablation rate is 0.096 mm / s. In Application Example 3, where the working layer is a zirconium diboride-silicon carbide-molybdenum disilicide working layer, the ablation time is 23.00 s and the average ablation rate is 0.128 mm / s. It is clear that the ablation times of Application Examples 1-3 are significantly shorter than those of Application Example 1.1, and the average ablation rates are higher. This demonstrates that the various substances in the ceramic powder of this application can play a good role in... The synergistic effect of the ceramic powder, especially the dual characteristics of molybdenum disilicide (MoSl) which possesses both metallic and ceramic properties, including high melting point, low density, and excellent resistance to high-temperature oxidation, is achieved by adding it to the system. This inhibits crack propagation in the working layer and enhances its oxidation resistance. Hafnium boride (HB) also possesses dual characteristics of ceramic and metallic properties, high melting point, and high hardness. In the working layer, it exhibits crack deflection and crack termination phenomena, effectively inhibiting and preventing crack propagation and significantly improving the oxidation resistance of the working layer. Overall, the working layer made from the ceramic powder of this application can be tightly bonded to the Cf / SiC composite material, inhibiting crack propagation in the working layer and exhibiting good stability and oxidation resistance in high-temperature environments. Changing the composition of the ceramic powder would not achieve the ablation resistance effect achievable by this application.
[0037] Based on this, the ceramic powders formed under different material ratios were studied and analyzed. First, as... Figures 1-1 to 1-9 As shown, the high-temperature resistant ceramic powder for plasma spraying prepared in this application has good sphericity, uniform particle size distribution, and excellent microstructure; as Figures 2-1 to 2-9 As shown, the working layer formed after spraying with the high-temperature plasma spraying ceramic powder prepared in this application has almost no voids or cracks, and the substrate provides good protection. Based on this, it can be seen that high-temperature plasma spraying ceramic powder and working layer with good morphology can be obtained within the material ratio range specified in this application, and the material ratio can then be further optimized and improved.
[0038] In Examples 1-9, this application used different auxiliary material ratios, and applied Examples 1-9 to the applications of Application Examples 1.1-1.9 for spraying, and kept all process parameters unchanged except for the ceramic powder used for high-temperature plasma spraying.
[0039] From Table 2.2 combined Figures 3-1 to 3-9It can be concluded that during ablation, the substrate surface in the ablation zone will first peel off, and the working layer will gradually peel off from the ablation point outwards. The ablation surface will exhibit a morphology of melting and re-solidification of the coating after peeling. At higher laser energies, molybdenum disilicide, silicon carbide, and zirconium diboride within the working layer will form corresponding glassy phases, eventually flowing and solidifying. Observation of the ablation morphology shows that the coating near the ablation hole in the working layer is peeled off. In application examples 1.1 and 1.5, the degree of peeling on the working layer surface is relatively mild, and the area around the peeled area is relatively smooth, providing good protection for the substrate. In the remaining application example 1, the working layer shows severe peeling, with the area around the peeled portion... Some fragmentation was observed in the coating area, and cracks appeared in all nine coatings. The coating in Application Example 1.1 showed less cracking, indicating that the composition of the coating in Application Example 1.1 provided better protection for the substrate. Data showed that Application Examples 1.1 and 1.6 had longer ablation times and lower average ablation rates of the working layer. Overall, Application Example 1.1 showed the best performance in terms of ablation resistance, proving that by strictly controlling the weight ratio of the main material and auxiliary material, as well as the weight ratio of molybdenum disilicide and hafnium boride, this application can indeed improve the ablation resistance time of Cf / SiC composite materials and reduce the average ablation rate.
[0040] Combined Figures 4-1 to 4-9 It can be seen that although the working layer pore distribution in Application Examples 1.1-1.9 is relatively dense and the porosity is below 6%, the working layer of Application Example 1.1 is significantly denser, with a porosity as low as 0.62%. Furthermore, the porosity of Application Examples 1.7-1.9 is significantly higher, proving that excessive molybdenum disilicide content does indeed lead to excessive binder phase content, resulting in particle accumulation and increased porosity of the working layer. The roughness of Application Example 1.4 is significantly higher than that of Application Example 1.3, the roughness of Application Example 1.6 is significantly higher than that of Application Example 1.1, and the roughness of Application Example 1.9 is significantly higher than that of Application Example 1.8, proving that excessive hafnium boride addition does indeed produce a repulsive effect with zirconium diboride, increasing the roughness of the working layer.
[0041] Based on the above data, it can be concluded that when the main material, molybdenum disilicide, and hafnium boride are compounded in a weight ratio of 100:20:5, the ceramic powder for high-temperature plasma spraying with the best comprehensive performance can be obtained. After spraying, the working layer with the lowest porosity, roughness, and average ablation rate and the highest ablation time can be obtained, giving the Cf / SiC composite material superior oxidation and ablation resistance.
[0042] Based on this, this application further optimized the parameters during the preparation of the working layer in step S3. In Application Examples 1.1 and 2.1-2.8, the high-temperature resistant ceramic powder for plasma spraying prepared in Example 1 was used. By adjusting the parameters, orthogonal experiments were conducted to verify the voltage, current, main gas flow rate, auxiliary gas flow rate, carrier gas flow rate and spraying distance, as shown in Application Examples 2.1-2.8 below.
[0043] <Application Examples 2.1-2.8> The application of a high-temperature resistant ceramic powder for plasma spraying differs from Application Example 1.1 in that the parameters in step S3 are different, as shown in Table 1-2, while the rest are the same as in Application Example 1.1.
[0044] Table 1-2 Spraying parameters for step S3 Performance testing 1. Laser ablation performance test: The samples obtained in test cases 2.1-2.8 were subjected to laser ablation. The laser used was a CO2 laser with a laser ablation power of 500W, a spot diameter of 2mm, and an Ar atmosphere. The ablation (burn-through) time (s) and the average ablation rate of the working layer (mm / s) were recorded. 2. Working layer porosity test: The porosity of the working layer obtained in test cases 2.1-2.8 is measured using image analysis, and microscopic scanning images are taken, such as... Figures 4-10 to 4-17 As shown, the porosity (%) of the working layer cross section was identified and calculated using ImagePro-Plus software; 3. Working layer roughness test: The surface roughness of the working layer obtained in application examples 2.1-2.8 is tested using a contact roughness tester. Five points are measured and the average value is calculated.
[0045] Table 2.3 Data Records - 3 According to the data in Table 2.3, Application Examples 1.1 and 2.6 have higher ablation times and lower average ablation rates of the working layer, while Application Examples 1.1 and 2.5 have lower porosity. Combined with... Figures 4-10 to 4-17 It can be seen that Application Examples 1.1, 2.5, and 2.8 have lower roughness. Overall, Application Example 1.1 has the best comprehensive performance, proving that by adjusting the process parameters and controlling the voltage of the supersonic plasma spraying to 90V, the current to 420A, the main gas flow rate to 80L / min, the auxiliary gas flow rate to 50L / min, the carrier gas flow rate to 12L / min, and the spraying distance to 100mm, the parameters of this application form a complete spraying scheme, which makes the working layer have the best appearance morphology, the lowest porosity, and the best ablation resistance, thus meeting the requirements of Cf / SiC composite materials in high-temperature and ultra-high-temperature strong oxidation applications.
[0046] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. A high-temperature resistant ceramic powder for plasma spraying, characterized in that, It includes main materials and auxiliary materials in a weight ratio of 100:(18-32), wherein the main materials include zirconium diboride and silicon carbide, and the auxiliary materials include molybdenum disilicide, and the particle size of zirconium diboride, silicon carbide and molybdenum disilicide is <100μm.
2. The high-temperature resistant ceramic powder for plasma spraying according to claim 1, characterized in that, The weight ratio of the main ingredient to the auxiliary ingredient is 100:
25.
3. The high-temperature resistant ceramic powder for plasma spraying according to claim 1, characterized in that, The excipients also include hafnium boride with a particle size of <100μm.
4. The high-temperature resistant ceramic powder for plasma spraying according to claim 3, characterized in that, The weight ratio of molybdenum disilicide to hafnium boride is 20:
5.
5. A method for preparing high-temperature resistant plasma spraying ceramic powder according to any one of claims 1-4, characterized in that, The process includes the following steps: mixing the main material, auxiliary material and lubricant, ball milling, then mixing with binder, dispersant and water for spray granulation, heat treatment, and sieving to obtain a high-temperature resistant ceramic powder for plasma spraying with a particle size distribution of 25-58μm.
6. The application of the high-temperature resistant plasma spraying ceramic powder according to any one of claims 1-4, characterized in that, Includes the following steps: S1. Matrix pretreatment; S2. Spraying the base coat: Using supersonic plasma spraying to spray the base coat onto the surface of the pre-treated substrate. S3. Spraying the working layer: The high-temperature resistant plasma spraying ceramic powder is sprayed onto the surface of the base layer using supersonic plasma spraying. The voltage of the supersonic plasma spraying is 80-110V, the current is 380-440A, the main gas flow rate is 80-100L / min, the auxiliary gas flow rate is 45-55L / min, the carrier gas flow rate is 8-12L / min, and the spraying distance is 100-130mm, resulting in a working layer with a thickness of 350-360μm.
7. The application of the high-temperature resistant ceramic powder for plasma spraying according to claim 6, characterized in that, In step S3, the voltage for supersonic plasma spraying is 90V.
8. The application of the high-temperature resistant ceramic powder for plasma spraying according to claim 6, characterized in that, In step S3, the current for supersonic plasma spraying is 420A.
9. The application of the high-temperature resistant ceramic powder for plasma spraying according to claim 6, characterized in that, In step S3, the main gas flow rate for supersonic plasma spraying is 80 L / min, the auxiliary gas flow rate is 50 L / min, and the carrier gas flow rate is 12 L / min.
10. The application of the high-temperature resistant ceramic powder for plasma spraying according to claim 6, characterized in that, In step S3, the spraying distance for supersonic plasma spraying is 100mm.