Ablation-resistant hafnium carbide composite ceramic material and preparation method and application thereof

Abstract

The application belongs to the technical field of composite ceramic materials, and particularly relates to an ablation-resistant hafnium carbide composite ceramic material and a preparation method and application thereof. The ablation-resistant hafnium carbide composite ceramic material is obtained by sintering raw material powder under a protective atmosphere after ball milling. The raw material powder comprises the following components in mass fraction: HfC powder 70-90 parts, HfB2 powder 5-20 parts, SiC powder 5-10 parts, and HfSi2 powder 0-20 parts. The application takes HfC as a high-melting-point main phase to provide a framework for the ceramic, so that the prepared composite ceramic material has the characteristics of high melting point, can withstand ablation above 2500 DEG C, and has excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of composite ceramic materials technology, specifically relating to an ablation-resistant hafnium carbide composite ceramic material, its preparation method, and its application. Background Technology

[0002] As the requirements for thermal protection materials used in supersonic aircraft become increasingly stringent, ceramic materials are required to withstand ablation at 2000–3000℃ while also possessing sufficient strength to ensure service life. The leading edge and tail fins of supersonic aircraft are typically subjected to erosion by hot airflow at 2200–3000℃, necessitating improvements in the ablation resistance limits of ceramic materials. Furthermore, under the impact of ultra-high-temperature hot airflow, components require specific mechanical properties to maintain structural and dimensional integrity. Therefore, designing thermal protection materials with ablation resistance, oxidation resistance, and certain mechanical properties, primarily composed of high-melting-point hafnium carbide, is crucial for enhancing the performance of new aircraft.

[0003] The rapid development of the aerospace industry has led to the emergence of ceramic matrix composites (CMCs) as a potential alternative to metals as novel high-temperature structural materials due to their high-temperature stability, oxidation and ablation resistance, and low density with high strength. While ceramic matrices possess inherent high-temperature resistance, they are also prone to brittleness. CMCs are typically prepared by adding or in-situ generating high-toughness reinforcing materials within a high-temperature resistant, brittle ceramic matrix. The ceramic matrix generally includes silicon carbide (SiC), other carbides, nitrides, and metal oxides. Aerospace devices made from silicon carbide ceramic composites oxidize under high-temperature conditions, and the toughening phases, such as the silicon carbide matrix, carbon fibers, and carbon nanotubes, lack long-term performance stability. Existing carbon / carbon composite systems used in some aircraft thermal protection components exhibit significant oxide layer detachment when ablation temperatures exceed 2500°C. Furthermore, the inherently poor mechanical properties of thermal protection materials make them susceptible to cracking and detachment from the matrix under the erosion of hot air currents, ultimately resulting in a loss of their oxidation and ablation resistance. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide an ablation-resistant hafnium carbide composite ceramic material, its preparation method and application. The ablation-resistant hafnium carbide composite ceramic material provided by this invention can provide excellent ablation resistance at temperatures above 2500℃, and also has excellent mechanical properties.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] This invention provides a method for preparing an ablation-resistant hafnium carbide composite ceramic material, comprising the following steps:

[0007] After ball milling the raw material powder, it was sintered under a protective gas to obtain ablation-resistant hafnium carbide composite ceramic material;

[0008] The raw material powder comprises the following components in parts by mass:

[0009] 70-90 parts of HfC powder, 5-20 parts of HfB2 powder, 5-10 parts of SiC powder, and 0-20 parts of HfSi2 powder.

[0010] Preferably, the particle size of the HfC powder, HfB2 powder, SiC powder, and HfSi2 powder is ≤30μm.

[0011] Preferably, the sintering includes: a first sintering, heating, and a second sintering; the temperature of the first sintering is 1300-1600℃, and the holding time is 0.5-2h; the temperature of the second sintering is 1700-2000℃, and the holding time is 1-3h.

[0012] Preferably, the heating rate is 5–15 °C / min.

[0013] Preferably, the ball milling is a wet ball milling; the solvent used in the wet ball milling is ethanol.

[0014] Preferably, the ratio of the volume of the solvent used in the wet ball mill to the mass of the raw material powder is (50-100) mL:(100-200) g.

[0015] Preferably, the ball milling speed is 100-150 rpm; the ball milling time is 8-12 hours.

[0016] Preferably, the raw material powder further includes additives; the additives include one or more of polyvinyl butyral, SiC whiskers, and carbon fiber composite materials.

[0017] The present invention also provides an ablation-resistant hafnium carbide composite ceramic material prepared by the preparation method described above, comprising a main component and secondary components; the main component is HfC; the secondary components include HfB2 and SiC, or HfB2, SiC and HfSi2.

[0018] The present invention also provides the application of the ablation-resistant hafnium carbide composite ceramic material described above in the thermal protection material of supersonic aircraft.

[0019] This invention provides a method for preparing an ablation-resistant hafnium carbide composite ceramic material, comprising the following steps: ball milling the raw material powder and sintering it under a protective gas to obtain the ablation-resistant hafnium carbide composite ceramic material; the raw material powder comprises the following components by mass: 70-90 parts of HfC powder, 5-20 parts of HfB2 powder, 5-10 parts of SiC powder and 0-20 parts of HfSi2 powder.

[0020] This invention uses HfC as the high-melting-point main phase to provide a framework for the ceramic, giving the prepared composite ceramic material a high melting point and enabling it to withstand ablation at temperatures above 2500℃. The HfB2 phase, with a lower melting point than HfC, is used to generate B2O3 during the ablation heating process to lower the surface temperature. SiC forms a SiO2 glass phase to fill voids, thus providing excellent ablation resistance and effectively preventing the heat shield layer from detaching. The added HfSi2 can fill particle gaps in the system, and the prepared composite ceramic material can form an HfSiO4 glass phase at high temperatures, further improving ablation resistance and preventing the heat shield layer from detaching. Therefore, even under extreme environments of ultra-high temperature, oxygen-rich, and high-speed airflow scouring, the ablation-resistant hafnium carbide composite ceramic material prepared by this invention has a uniform distribution of each component and can still form an antioxidant and ablation-resistant oxide protective layer on the substrate surface with uniform oxide phase distribution, high oxide melting point, and high self-healing melt viscosity. It exhibits excellent ablation resistance and superior mechanical properties in ultra-high temperature environments above 2500℃.

[0021] Furthermore, the present invention utilizes SiC whiskers and carbon fiber composite materials as additives during the preparation process, which can promote the improvement of the mechanical properties of ablation-resistant hafnium carbide composite ceramic materials. Attached Figure Description

[0022] Figure 1 The XRD patterns of the ablation-resistant hafnium carbide composite ceramic material of Example 1 of the present invention before and after ablation in an oxyhydrogen flame at 2500℃ for 2 min are shown.

[0023] Figure 2 The images show the morphology of the ablation-resistant hafnium carbide composite ceramic material of Example 1 of the present invention before and after ablation in an oxyhydrogen flame at 2500°C for 2 minutes.

[0024] Figure 3 The images show SEM images of the ablation-resistant hafnium carbide composite ceramic material of Example 1 of the present invention before and after ablation in an oxyhydrogen flame at 2500℃ for 2 minutes.

[0025] Figure 4 This is a morphology image of the hafnium carbide composite ceramic material in Comparative Example 1 of the present invention after being ablated in an oxyhydrogen flame at 2500°C for 2 minutes. Detailed Implementation

[0026] This invention provides a method for preparing an ablation-resistant hafnium carbide composite ceramic material, comprising the following steps:

[0027] After ball milling the raw material powder, it was sintered under a protective gas to obtain ablation-resistant hafnium carbide composite ceramic material;

[0028] The raw material powder comprises the following components in parts by mass:

[0029] 70-90 parts of HfC powder, 5-20 parts of HfB2 powder, 5-10 parts of SiC powder, and 0-20 parts of HfSi2 powder.

[0030] Unless otherwise specified, the present invention does not have special requirements on the source of the raw materials used in the preparation, and commercially available products well known to those skilled in the art can be used.

[0031] This invention involves ball milling the raw material powder to obtain ball-milled powder.

[0032] In this invention, the raw material powder comprises the following components in parts by mass:

[0033] The mixture consists of 70-90 parts of HfC powder, 5-20 parts of HfB2 powder, 5-10 parts of SiC powder, and 0-20 parts of HfSi2 powder, preferably 70-80 parts of HfC powder, 5-15 parts of HfB2 powder, 5-10 parts of SiC powder, and 0-5 parts of HfSi2 powder.

[0034] In this invention, the particle size of the HfC powder, HfB2 powder, SiC powder and HfSi2 powder is preferably ≤30μm, more preferably 20-30μm, and the purity is preferably ≥99.99%.

[0035] In this invention, the raw material powder preferably further includes additives; the additives preferably include one or more of polyvinyl butyral (PVB), SiC whiskers, and carbon fiber composite materials, more preferably polyvinyl butyral (PVB), SiC whiskers, or carbon fiber composite materials; the carbon fiber composite materials and SiC whiskers are purchased from Shanghai Yaotian New Material Technology Co., Ltd., and the polyvinyl butyral (PVB) is purchased from the National Pharmaceutical Reagent Network, with chemical purity; the mass of the polyvinyl butyral (PVB) is preferably 0-1% of the mass of the raw material powder, more preferably 0.1-0.5%; the mass of the SiC whiskers is preferably 0-1% of the mass of the raw material powder, more preferably 0.1-0.5%; the diameter of the SiC whiskers is preferably 10nm-2μm, more preferably 100nm-1μm; the mass of the carbon fiber composite material is preferably 0-1% of the mass of the raw material powder, more preferably 0.1-0.5%.

[0036] This invention controls the amount of each substance in the additive within the above range. Too much PVB will generate a large amount of CO2, resulting in porous ceramics that are not dense. Too much SiC whiskers will cause the ceramic material to crack. Adding too much carbon fiber composite material will react with HfSi2 to generate HfC and SiC, affecting the composition ratio of each substance in the ceramic system.

[0037] In this invention, the ball milling is preferably wet ball milling; the solvent used in the wet ball milling is preferably ethanol; the volume ratio of the solvent used in the wet ball milling to the mass ratio of the raw material powder is preferably (50-100) mL:(100-200) g, more preferably 50 mL:100 g; the rotation speed of the ball milling is preferably 100-150 rpm, more preferably 120-130 rpm; the ball milling time is preferably 8-12 h, more preferably 10-12 h; the ball milling is preferably carried out in a tungsten carbide ball milling jar; the ball-to-material ratio of the ball milling is preferably 1:(20-50), more preferably 1:(20-30).

[0038] After ball milling, the present invention preferably involves drying, grinding, and sieving the ball-milled raw material powder in sequence; the drying is preferably oven drying; the drying temperature is preferably 100-150℃, more preferably 120-140℃; the drying time is preferably 12-48h, more preferably 12-24h; the grinding is preferably done with a mortar and pestle; and the sieving is preferably done with a 50-mesh sieve.

[0039] This invention dissolves PVB particles on a screen in ethanol, which is then used as a wet ball milling dispersion solvent. This ethanol is then mixed with HfC powder, HfB2 powder, SiC powder, HfSi2 powder, SiC whiskers, and carbon fiber composite materials. This ensures that the molded block is free of large PVB particles and avoids cracking after molding.

[0040] After obtaining the ball-milled powder, the present invention sintersulates the ball-milled powder under a protective gas to obtain ablation-resistant hafnium carbide composite ceramic material.

[0041] In this invention, the protective gas is preferably argon; the purity of the argon is preferably 98-99.9%, more preferably 99.5-99.9%; the sintering includes: a first sintering, heating, and a second sintering; the temperature of the first sintering is 1300-1600℃, and the holding time is 0.5-2h; the temperature of the second sintering is 1700-2000℃, and the holding time is 1-3h; the heating rate to the first sintering temperature is preferably 10-30℃ / min, more preferably 15-25℃ / min; the heating rate is preferably 5-15℃ / min, more preferably 5-10℃ / min; the sintering is preferably carried out in a vacuum carbon tube furnace.

[0042] Before sintering, the present invention preferably places the ball-milled powder in a mold and presses it into shape, and then performs cold isostatic pressing on the resulting block material. In the present invention, the diameter of the mold is preferably 20-40 mm, more preferably 20 mm, 30 mm or 40 mm; the pressing pressure is preferably 25-35 MPa, more preferably 30 MPa; the cold isostatic pressing is preferably performed using a cold isostatic press; the pressure of the cold isostatic pressing is preferably 150-250 MPa, more preferably 180-230 MPa, and the holding time is preferably 30-50 min, more preferably 35-45 min.

[0043] In the ablation-resistant hafnium carbide composite ceramic material prepared by this invention, HfC serves as the high-melting-point main phase, providing a framework for the ceramic and giving the composite ceramic material a high melting point, capable of withstanding ablation at temperatures above 2500℃. The HfB2 phase, with a lower melting point than HfC, is used to generate B2O3 during the ablation heating process to lower the surface temperature. SiC forms a SiO2 glass phase to fill voids, thus providing excellent ablation resistance and effectively preventing the heat shield layer from detaching. The added HfSi2 can fill particle gaps in the system, and the composite ceramic material prepared accordingly can form an HfSiO4 glass phase at high temperatures, further improving ablation resistance and preventing cracking and detachment of the heat shield layer. Therefore, even in extreme environments of ultra-high temperature, oxygen-rich, and high-speed airflow erosion, the ablation-resistant hafnium carbide composite ceramic material prepared by this invention can still achieve the formation of a uniformly distributed oxide layer phase, a high-melting-point oxide layer, and a high self-healing melt viscosity on the substrate surface, exhibiting excellent ablation resistance.

[0044] The present invention also provides an ablation-resistant hafnium carbide composite ceramic material prepared by the preparation method described above, comprising a main component and secondary components; the main component is HfC; the secondary components include HfB2 and SiC, or HfB2, SiC and HfSi2.

[0045] The present invention also provides the application of the ablation-resistant hafnium carbide composite ceramic material described above in the thermal protection material of supersonic aircraft.

[0046] The present invention does not impose any particular limitation on the application of the ablation-resistant hafnium carbide composite ceramic material in the thermal protection material of supersonic aircraft; any application method known in the art can be used.

[0047] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0048] Example 1

[0049] HfC, HfB2, SiC, and HfSi2 in a mass ratio of 75:10:10:5 were weighed as raw material powders. The particle size of HfC powder, HfB2 powder, SiC powder, and HfSi2 powder was ≤30μm. PVB, SiC whiskers (diameter of 10nm~2μm), carbon fiber composite material, and ethanol were weighed as additives at a total mass of 0.5%, 0.5%, and 0% respectively. Carbon fiber composite material and SiC whiskers were purchased from Shanghai Yaotian New Material Technology Co., Ltd., and polyvinyl butyral (PVB) was purchased from the National Pharmaceutical Reagent Network with chemical purity. The volume ratio of ethanol to the mass of raw material powder was 50mL:100g.

[0050] The raw material powder and additives are mixed to form a mixture, which is then placed in a tungsten carbide ball mill jar and wet-milled using a ball mill. The ball-to-material ratio is 1:20, the ball mill speed is 150 rpm, and the ball milling time is 12 hours. After the mixture is evenly mixed, it is placed in a 120℃ drying oven and dried for 12 hours. The mixture is then ground into a fine powder using a mortar and pestle. The finely ground particles are passed through a 50-mesh sieve.

[0051] The mixed powder was placed in a mold with a diameter of 20 mm and pressed into a block using a pressure of 35 MPa. Then, it was placed in a cold isostatic press and treated at 250 MPa for 30 min to form a solid. Finally, it was sintered in a vacuum carbon tube furnace under 99.9% pure argon gas. The temperature was first raised to 1300℃ at a heating rate of 10℃ / min and held for 0.5 h. Then, the temperature was raised to 1700℃ at a heating rate of 5℃ / min and held for 2 h to obtain ablation-resistant hafnium carbide composite ceramic material.

[0052] The obtained ablation-resistant hafnium carbide composite ceramic material exhibited a mass ablation rate of -0.11 mg / s under oxyhydrogen flame conditions at 2500℃ for 5 min, a hardness of 1500 HV, and a compressive strength of 222.25 kN / cm². 2 .

[0053] Example 2

[0054] The difference from Example 1 is as follows:

[0055] (1) The mass ratio of HfC, HfB2, SiC and HfSi2 in the raw material powder is 70:10:10:10. Additives are added to the raw material, including PVB, SiC whiskers and carbon fiber composite materials accounting for 0.5%, 0% and 0.5% of the total mass of the raw material powder, respectively. After the additives and ethanol are mixed evenly, they are added to the raw material powder for wet ball milling.

[0056] (2) Sintering is performed by first heating the furnace temperature to 1500℃ at a heating rate of 15℃ / min and holding it for 1 hour, and then heating it to 2000℃ at a heating rate of 5℃ / min and holding it for 2 hours.

[0057] The obtained ablation-resistant hafnium carbide composite ceramic material exhibited a mass ablation rate of -0.21 mg / s after 5 min of ablation in an oxyhydrogen flame at 2500℃, a hardness of 1800 HV, and a compressive strength of 212.13 kN / cm². 2 .

[0058] Example 3

[0059] The difference from Example 1 is as follows:

[0060] (1) The mass ratio of HfC, HfB2, SiC and HfSi2 in the raw material powder is 80:5:5:10. Additives are added to the raw material, including PVB, SiC whiskers and carbon fiber composite materials accounting for 0.5%, 0.5% and 0.5% of the total mass of the raw material powder, respectively. After the additives and ethanol are mixed evenly, they are added to the raw material powder for wet ball milling.

[0061] (2) Sintering is performed by first heating the furnace temperature to 1400℃ at a heating rate of 12℃ / min and holding it for 1 hour, and then heating it to 1800℃ at a heating rate of 5℃ / min and holding it for 1 hour.

[0062] The obtained ablation-resistant hafnium carbide composite ceramic material exhibited a mass ablation rate of -0.33 mg / s after 5 min of ablation in an oxyhydrogen flame at 2500℃, a hardness of 1750 HV, and a compressive strength of 203.66 kN / cm². 2 .

[0063] Example 4

[0064] The difference from Example 1 is as follows:

[0065] (1) The mass ratio of HfC, HfB2, SiC and HfSi2 in the raw material powder is 70:5:5:20. Additives are added to the raw material, including PVB, SiC whiskers and carbon fiber composite materials accounting for 0.5%, 0.5% and 1% of the total mass of the raw material powder, respectively. After the additives and ethanol are mixed evenly, they are added to the raw material powder for wet ball milling.

[0066] (2) Sintering is performed by first heating the furnace temperature to 1400℃ at a heating rate of 12℃ / min and holding it for 1 hour, and then heating it to 1800℃ at a heating rate of 5℃ / min and holding it for 1 hour.

[0067] The obtained ablation-resistant hafnium carbide composite ceramic material exhibited a mass ablation rate of -0.23 mg / s after 5 min of ablation in an oxyhydrogen flame at 2500℃, a hardness of 2100 HV, and a compressive strength of 203.62 kN / cm². 2 .

[0068] Example 5

[0069] The difference from Example 1 is as follows:

[0070] (1) The mass ratio of HfC, HfB2, SiC and HfSi2 in the raw material powder is 75:5:5:15. Additives are added to the raw material, including PVB, SiC whiskers and carbon fiber composite materials accounting for 0.5%, 0% and 0% of the total mass of the raw material powder, respectively. After the additives and ethanol are mixed evenly, they are added to the raw material powder for wet ball milling.

[0071] (2) Sintering is performed as follows: The furnace temperature is first raised to 1600℃ at a heating rate of 12℃ / min and held for 1 hour, and then raised to 2000℃ at a heating rate of 5℃ / min and held for 1 hour.

[0072] The obtained ablation-resistant hafnium carbide composite ceramic material exhibited a mass ablation rate of -0.15 mg / s after 5 min of ablation in an oxyhydrogen flame at 2500℃, a hardness of 1700 HV, and a compressive strength of 221.54 kN / cm². 2 .

[0073] Comparative Example 1

[0074] HfC, HfB2, SiC, and HfSi2 in a mass ratio of 90:10:0:0 were weighed as raw material powders. PVB, SiC whiskers (diameter of 10nm to 2μm), carbon fiber composite material, and ethanol were weighed as additives, with a total mass of 0.5%, 0.5%, and 0.5% of the raw material powders, respectively. The volume ratio of ethanol to the mass of the raw material powders was 50mL:100g.

[0075] The raw material powder and additives are mixed to form a mixture, and then placed in a tungsten carbide ball mill jar and wet-milled with a ball mill. The ball-to-material ratio during wet milling is 1:20. After the ball milling is uniform, the mixture is placed in a (120)℃ drying oven for 12 hours and then ground with a mortar and pestle. The ground particles pass through a 50-mesh sieve.

[0076] The mixed powder was placed in a mold with a diameter of 20 mm and pressed into a block using a pressure of 35 MPa. Then, it was placed in a cold isostatic press and treated at 250 MPa for 30 min to form the block. Finally, it was sintered in a vacuum carbon tube furnace under 99.9% pure argon gas. The temperature was first raised to 1300℃ at a heating rate of 10℃ / min and held for 0.5 h. Then, the temperature was raised to 1700℃ at a heating rate of 5℃ / min and held for 2 h to obtain hafnium carbide composite ceramic material.

[0077] The obtained ablation-resistant hafnium carbide composite ceramic material exhibited a mass ablation rate of -6.11 mg / s under oxyhydrogen flame conditions at 2500℃ for 5 min, a hardness of 2000 HV, and a compressive strength of 122.25 kN / cm². 2 .

[0078] In the comparative example, the lack of raw materials such as SiC and HfSi2 in the raw material powder prevented the ceramic system from forming a glassy phase during the ablation process, thus severely reducing its ablation resistance.

[0079] Performance testing

[0080] (1) The properties of the ablation-resistant hafnium carbide composite ceramic materials prepared in Examples 1 to 5 were tested, and the results are shown in Table 1.

[0081] Table 1. Performance test results of the ablation-resistant hafnium carbide composite ceramic materials prepared in Examples 1-5

[0082] Sample Ultra-high temperature resistance (°C) <![CDATA[Fracture toughness (MPa / m 2 )]]> Thermal conductivity (W / m·K) Example 1 2950 4.8 1.6 Example 2 2930 4.6 1.8 Example 3 2880 4.7 1.4 Example 4 2830 4.5 1.2 Example 5 2800 4.4 1.0 Comparative Example 1 2500 4.6 1.4

[0083] The ultra-high temperature resistance in Table 1 refers to the temperature at which the sample cracks and the oxide layer peels off after 2 minutes of treatment.

[0084] As shown in Table 1, in Examples 1-5, the high-temperature resistance and fracture toughness of the ceramic materials decreased with the increase of HfSi2 mass fraction. This indicates that the HfC, HfB2, SiC, and HfSi2 ceramic system in this invention has excellent ablation resistance. However, excessively high HfSi2 content leads to a decrease in the ablation resistance and mechanical properties of the material. In addition, the thermal conductivity of the ceramic material decreases when the HfSi2 content increases.

[0085] (2) XRD tests were performed on the ablation-resistant hafnium carbide composite ceramic material of Example 1 before and after ablation in an oxyhydrogen flame at 2500℃ for 2 minutes. The results are as follows: Figure 1 As shown.

[0086] Depend on Figure 1 It can be seen that the ablation-resistant hafnium carbide composite ceramic material of Example 1, before ablation, mainly consists of HfC, HfB2, and SiC phases, and after ablation, the main phase composition is (Hf... 0.9 Si 0.1 O2 and SiC. Among them (Hf 0.9 Si 0.1 O2 is formed by the dissolution of the HfO2 glass phase generated after the oxidation of HfC and HfB2 into the SiO2 glass phase.

[0087] (3) The morphology of the ablation-resistant hafnium carbide composite ceramic material of Example 1 before and after ablation in an oxyhydrogen flame at 2500℃ for 2 minutes is as follows: Figure 2 As shown, a represents the area before ablation, and b represents the area after ablation.

[0088] Depend on Figure 2 It can be seen that the morphology of the ablation-resistant hafnium carbide composite ceramic material in Example 1 before ablation is ( Figure 2a) The surface is smooth and dense, without cracking or peeling. Morphology after 2 min of oxyhydrogen flame ablation at 2500℃ ( Figure 2 b) The ceramic material surface still maintains an intact block. This is because during the oxidation process at 2500℃, a highly viscous HfSiO4 glass phase is formed on the ceramic surface and is prevented from falling off. Therefore, the ceramic material has excellent ablation resistance.

[0089] (3) The microstructure of the ablation-resistant hafnium carbide composite ceramic material of Example 1 before and after ablation in an oxyhydrogen flame at 2500℃ for 2 min was measured by scanning electron microscopy (SEM). The SEM results are as follows: Figure 3 As shown, a represents the state before ablation, b represents the state after ablation, and c represents the glassy microcrystalline morphology formed on the ceramic surface after ablation.

[0090] Depend on Figure 3 It can be seen that the SEM image of the ablation-resistant hafnium carbide composite ceramic material in Example 1 before ablation ( Figure 3 a) The resulting ceramic surface consists of large ceramic blocks without obvious pores or cracks. Morphology of hafnium carbide composite ceramic material after ablation in an oxyhydrogen flame at 2500℃ for 2 minutes ( Figure 3 b) A large number of microcrystals precipitate on the surface of the ceramic material. This is because during the oxidation process at 2500℃, highly viscous HfSiO4 glass phase microcrystals form on the ceramic surface, effectively adhering to the ceramic particles and preventing them from detaching and moving. Therefore, the ceramic material has excellent ablation resistance. SEM and EDS images of the microcrystals generated after ablation of the hafnium carbide composite ceramic material at 2500℃ for 2 minutes are shown. Figure 3 c) A large number of microcrystals precipitate on the surface of the ceramic material. These microcrystals consist of 13.33 wt% C, 24.62 wt% O, 16.06 wt% Si, and 46 wt% Hf. This indicates that the main phase formed on the surface of the ceramic particles is a glassy phase composed of Hf, Si, and O elements.

[0091] (4) The morphology of the hafnium carbide composite ceramic material in Comparative Example 1 after ablation in an oxyhydrogen flame at 2500℃ for 2 min is as follows: Figure 4 As shown.

[0092] Depend on Figure 4 It can be seen that the ablation morphology of the hafnium carbide composite ceramic material in Comparative Example 1 shows cracks and fissures. After ablation in an oxyhydrogen flame at 2500℃, the ceramic surface exhibits obvious cracking and oxide layer detachment. This is because the system lacks substances that generate a glassy phase. After high-temperature oxidation, the generated HfO2 rapidly detaches, causing the ceramic matrix to be eroded by the high-temperature gas flow, ultimately resulting in poor ablation resistance of the sample.

[0093] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing an ablation-resistant hafnium carbide composite ceramic material, characterized in that, Includes the following steps: After ball milling the raw material powder, it was sintered under a protective gas to obtain ablation-resistant hafnium carbide composite ceramic material; The raw material powder comprises the following components in parts by mass: The mixture contains 70-90 parts of HfC powder, 5-20 parts of HfB2 powder, 5-10 parts of SiC powder, and 5-20 parts of HfSi2 powder; the particle size of the HfC powder, HfB2 powder, SiC powder, and HfSi2 powder is independently 20-30 μm. The ablation-resistant hafnium carbide composite ceramic material includes a main component and secondary components; the main component is HfC; the secondary components include HfB2, SiC and HfSi2.

2. The preparation method according to claim 1, characterized in that, The sintering process includes: a first sintering, heating, and a second sintering; The first sintering temperature is 1300~1600℃, and the holding time is 0.5~2h; The second sintering temperature is 1700~2000℃, and the holding time is 1~3h.

3. The preparation method according to claim 2, characterized in that, The heating rate is 5~15℃ / min.

4. The preparation method according to claim 1, characterized in that, The ball milling is a wet ball milling; the solvent used in the wet ball milling is ethanol.

5. The preparation method according to claim 4, characterized in that, The ratio of the volume of the solvent used in the wet ball mill to the mass of the raw material powder is (50~100) mL:(100~200) g.

6. The preparation method according to claim 1 or 4, characterized in that, The ball mill rotates at a speed of 100-150 rpm; The ball milling time is 8-12 hours.

7. The preparation method according to claim 1, characterized in that, The raw material powder also includes additives; the additives include one or more of polyvinyl butyral, SiC whiskers, and carbon fiber composite materials.

8. The ablation-resistant hafnium carbide composite ceramic material prepared by the preparation method according to any one of claims 1 to 7, characterized in that, It includes a main component and secondary components; the main component is HfC; the secondary components include HfB2, SiC and HfSi2.

9. The application of the ablation-resistant hafnium carbide composite ceramic material of claim 8 in the thermal protection material of supersonic aircraft.

Images