A method for producing an aluminum silicon carbide composite

Abstract

The application discloses a preparation method of an aluminum silicon carbide composite material, and particularly relates to the following steps: S1, preparing a silicon carbide blank: silicon carbide particles are prepared into a silicon carbide blank through a forming method; S2, aluminum infiltration: the obtained silicon carbide blank is subjected to aluminum infiltration treatment to obtain an aluminum silicon carbide blank; S3, residual aluminum adsorption: the aluminum silicon carbide blank obtained through the aluminum infiltration treatment in step S2 is buried in an adsorbent for adsorption treatment; and S4, post-treatment: the aluminum silicon carbide blank subjected to the adsorption treatment is subjected to wet heat treatment and mechanical treatment to obtain the aluminum silicon carbide composite material. Compared with the prior art, the aluminum silicon carbide composite material obtained through the preparation method can achieve the purpose of removing residual aluminum on the surface of the aluminum silicon carbide composite material, and is convenient for subsequent utilization and processing of the composite material.

Description

Technical Field

[0001] This invention belongs to the field of aluminum silicon carbide material technology, and particularly relates to a method for preparing aluminum silicon carbide composite materials. Background Technology

[0002] Aluminum-silicon carbide composites combine the advantages of aluminum alloys and silicon carbide, exhibiting low density, high thermal conductivity, high strength, good thermal stability, and wear resistance. They are widely used in critical fields such as aerospace, automotive, and shipbuilding. High-volume-fraction silicon carbide-reinforced aluminum-silicon carbide composites are commonly used in IGBT (Insulated Gate Bipolar Transistor) packaging and radar packaging housings, operating stably at temperatures ranging from 300℃ to 350℃. Aluminum-silicon carbide composites with approximately 50% silicon carbide volume content are used in optical and precision instrument components and microwave devices, demonstrating excellent performance in terms of temperature disturbance and vibration shock resistance. However, high-silicon carbide volume fraction aluminum-silicon carbide components exhibit properties closer to ceramics, with higher hardness but poorer plasticity and ductility, making preparation, molding, and processing more difficult and limiting their application scenarios. Currently, these products are mainly prepared using pressure infiltration, where porous silicon carbide green blanks are first prepared, and then molten aluminum is infiltrated into the green blanks through pressure infiltration to obtain the aluminum-silicon carbide composite material. Due to limitations of pressure impregnation equipment, for more complex green structures, especially semi-enclosed structures, a large amount of residual aluminum will remain after impregnation, making subsequent processing very troublesome. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing aluminum silicon carbide composite materials, which can remove residual aluminum from the surface of the aluminum silicon carbide composite materials, facilitating subsequent processing and use of the aluminum silicon carbide composite materials.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is: a method for preparing aluminum silicon carbide composite material, the preparation method specifically including the following steps:

[0005] S1. Preparation of silicon carbide blank: Silicon carbide particles are used to prepare silicon carbide blanks by forming method;

[0006] S2, Aluminizing: The obtained silicon carbide blank is subjected to aluminizing treatment to obtain aluminum silicon carbide blank;

[0007] S3, Residual Aluminum Adsorption: The aluminum silicon carbide blank obtained by aluminizing in step S2 is embedded in an adsorbent for adsorption treatment.

[0008] S4. Post-treatment: The aluminum silicon carbide blanks that have undergone adsorption treatment are subjected to wet heat treatment to obtain aluminum silicon carbide composite materials.

[0009] Preferably, in step S1, the molding method is selected from one of compression molding, injection molding, slip casting, and 3D printing.

[0010] Preferably, step S1 further includes an oxidation treatment of the silicon carbide particles or silicon carbide blank to obtain an oxide layer. The specific steps of the oxidation treatment are: oxidation at 800-120℃ for 1-10 hours; the thickness of the oxide layer is 150-1000 nm. The generated aluminum carbide reacts with water in the atmosphere, causing the material to crack and pulverize in everyday environments. This invention uses the above-mentioned oxidation treatment method, by oxidizing the silicon carbide particles before preparing the silicon carbide blank, or oxidizing the obtained silicon carbide blank, which can improve the wettability with molten aluminum during aluminizing and inhibit the harmful reaction between silicon carbide and aluminum to form aluminum carbide.

[0011] Preferably, in step S2, the aluminum material used for aluminizing is cast aluminum, and the Si content in the cast aluminum is 5-20%.

[0012] Preferably, in step S3, the adsorbent includes a base powder and a penetration enhancer, wherein the content of the penetration enhancer is 5-30% of the content of the base powder. The adsorbent of this invention includes a base powder and a penetration enhancer, and further specifies the content of the penetration enhancer. The aforementioned content of penetration enhancer helps residual aluminum penetrate into the base powder, thereby improving the residual aluminum removal efficiency.

[0013] Preferably, the base powder comprises silicon carbide powder, binder, dispersant, and carbon source, and the ratio of silicon carbide powder, binder, dispersant, and carbon source is (50-80):(1-10):(1-5):(10-20). The present invention uses a base powder composition with the above ratio, which can further improve the adsorption effect of residual aluminum in the adsorbent, thereby completely removing residual aluminum from the surface of the aluminum silicon carbide blank.

[0014] Preferably, the penetration enhancer is magnesium particles or fluorozirconate particles, and the particle size of the penetration enhancer is 0.5-5 mm.

[0015] Preferably, the silicon carbide powder has a particle size of 0.5-100 μm, the binder is selected from at least one of polyvinyl alcohol, polyethylene oxide, and hydroxypropyl methylcellulose, the dispersant is selected from at least one of ammonia, glycerol, polyethylene glycol, sodium hexaphosphate metaate, ammonium acrylate, glycerol, quaternary ammonium salt, polyacrylate, polyethyleneimine, and BYK, and the carbon source is selected from at least one of petroleum coke, graphite powder, spray carbon black, dextrin, sugars, and phenolic resin.

[0016] This invention utilizes the adsorbent composed as described above to allow residual aluminum on the surface of the aluminum silicon carbide blank to infiltrate into the adsorbent powder, forming secondary aluminum silicon carbide. Because the adsorbent contains a carbon source and the silicon carbide surface is not oxidized, during high-temperature treatment, the residual carbon in the adsorbent powder and the silicon carbide readily react with aluminum to form aluminum carbide, which is distributed at the interface between the aluminum and the adsorbent powder. This facilitates the subsequent removal of secondary aluminum silicon carbide through hydrothermal treatment.

[0017] Preferably, in step S3, the loose packing density of the adsorbent is less than the density of the silicon carbide blank. This invention ensures that the loose packing density of the adsorbent is less than that of the silicon carbide blank, resulting in a higher porosity for the adsorbent compared to the blank. During aluminizing, the adsorbent's capillary force on the molten aluminum is less than that of the silicon carbide blank, thus preventing the adsorbent from drawing out aluminum from the silicon carbide blank and only removing residual aluminum from the product surface.

[0018] Preferably, in step S3, the specific steps of the adsorption treatment are as follows: embedding the aluminum silicon carbide blank in the adsorbent, heating it to 800-1500℃ under a nitrogen atmosphere, and holding it at that temperature for 0.5-8h.

[0019] Preferably, in step S4, the specific steps of the damp heat treatment are as follows: the aluminum silicon carbide blank that has undergone adsorption treatment is placed in a high-temperature salt spray drying oven and left for 2-5 days under conditions of relative humidity of 60-100%RH and temperature of 80-150℃. This invention requires damp heat treatment because heat treatment under dry conditions is ineffective or even completely ineffective; damp heat conditions involving water vapor are necessary to achieve the purpose of this application.

[0020] This invention employs the aforementioned hydrothermal treatment, utilizing the phenomenon of water reacting with aluminum carbide to pulverize the composite material. Moisture enters the secondary aluminum silicon carbide, and the aluminum carbide generated by the reaction rapidly hydrolyzes and breaks down under high temperature and high humidity conditions. Since aluminum carbide mainly exists at the interface between the adsorbent powder and aluminum, the destruction of aluminum carbide will cause the secondary aluminum silicon carbide to pulverize. However, the aluminum silicon carbide body itself undergoes peroxidation treatment, making it difficult to react with aluminum to generate aluminum carbide. The aluminum carbide content inside the body is very low, and the product has high density, so moisture does not easily enter the interior. Therefore, pulverization will not occur. Thus, hydrothermal treatment can remove the secondary aluminum silicon carbide powder without damaging the aluminum silicon carbide product itself.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The present invention oxidizes silicon carbide particles before preparing silicon carbide blanks or oxidizes silicon oxide blanks, which can improve the wettability with aluminum liquid during aluminizing and reduce the harmful reaction of silicon carbide and aluminum to form aluminum carbide, thereby avoiding sample pulverization caused by subsequent hydrothermal treatment.

[0023] 2. This invention, through the rational formulation of the adsorbent, allows the residual aluminum on the surface of the aluminum silicon carbide blank to penetrate into the powder of the adsorbent, forming secondary aluminum silicon carbide. The secondary aluminum silicon carbide is then removed through subsequent wet heat treatment, thereby achieving the purpose of removing residual aluminum from the surface of the aluminum silicon carbide composite material, which facilitates the subsequent use and processing of the composite material. Attached Figure Description

[0024] Figure 1These are macroscopic photographs of untreated aluminum silicon carbide composite materials;

[0025] Figure 2 This is a macroscopic photograph of the treated aluminum silicon carbide composite material prepared in Example 1 of the present invention. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0027] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This application specification and embodiments are merely exemplary.

[0029] This invention provides a method for preparing an aluminum-silicon carbide composite material, which specifically includes the following steps:

[0030] S1. Preparation of silicon carbide preform: Silicon carbide particles are used to prepare silicon carbide preforms by compression molding, injection molding, slip casting or 3D printing.

[0031] S2, Aluminizing: The obtained silicon carbide billet is aluminized to obtain aluminum silicon carbide billet. The aluminum material used for aluminizing is cast aluminum, and the Si content in the cast aluminum is 5-20%.

[0032] S3, Residual Aluminum Adsorption: The aluminum silicon carbide blank obtained by aluminizing treatment in step S2 is buried in an adsorbent for adsorption treatment. The specific steps of the adsorption treatment are as follows: the aluminum silicon carbide blank is buried in the adsorbent, and the temperature is raised to 800-1500℃ under a nitrogen atmosphere and kept at the temperature for 0.5-8h.

[0033] S4. Post-treatment: The aluminum silicon carbide blanks that have undergone adsorption treatment are subjected to wet heat treatment to obtain aluminum silicon carbide composite materials.

[0034] In a specific embodiment, step S1 further includes an oxidation treatment of silicon carbide particles or silicon carbide blanks to obtain an oxide layer. The specific steps of the oxidation treatment are: oxidation at 800-120℃ for 1-10 hours; the thickness of the oxide layer is 150-1000 nm. During the aluminizing process of silicon carbide green blanks, silicon carbide reacts with aluminum to form silicon carbide. Aluminum carbide reacts with water in the atmosphere, causing the material to crack and pulverize in daily environments. This invention uses the above-mentioned oxidation treatment method, by oxidizing the silicon carbide particles before preparing the silicon carbide blank, or oxidizing the obtained silicon oxide blank, which can improve the wettability with molten aluminum during aluminizing and inhibit the harmful reaction between silicon carbide and aluminum to form aluminum carbide.

[0035] In a specific embodiment, in step S3, the adsorbent includes a base powder and a penetration enhancer, with the penetration enhancer content being 5-30% of the base powder content. The base powder includes silicon carbide powder, a binder, a dispersant, and a carbon source, and the ratio of silicon carbide powder, binder, dispersant, and carbon source is (50-80):(1-10):(1-5):(10-20). The penetration enhancer is magnesium particles or fluorozirconate particles, with a particle size of 0.5-5 mm. The silicon carbide powder has a particle size of 0.5-100 μm. The binder is selected from at least one of polyvinyl alcohol, polyethylene oxide, and hydroxypropyl methylcellulose. The dispersant is selected from at least one of ammonia, glycerol, polyethylene glycol, sodium hexaphosphate metaate, ammonium acrylate, glycerol, quaternary ammonium salt, polyacrylate, polyethyleneimine, and BYK. The carbon source is selected from at least one of petroleum coke, graphite powder, spray carbon black, dextrin, sugars, and phenolic resin.

[0036] The present invention uses the above-mentioned proportions of basic powder composition, which can further improve the adsorption effect of residual aluminum in the adsorbent, thereby completely removing the residual aluminum on the surface of the aluminum silicon carbide blank. At the same time, the present invention utilizes the above-mentioned composition of the adsorbent to allow the residual aluminum on the surface of the aluminum silicon carbide blank to penetrate into the powder of the adsorbent, forming secondary aluminum silicon carbide. Meanwhile, the adsorbent contains a carbon source, and the silicon carbide surface is not oxidized. During high-temperature treatment, the residual carbon in the powder of the adsorbent and the silicon carbide can easily react with aluminum to form aluminum carbide, which is beneficial for subsequent removal by wet heat treatment.

[0037] In a specific embodiment, in step S3, the loose packing density of the adsorbent is less than the density of the silicon carbide blank. This invention ensures that the loose packing density of the adsorbent is less than that of the silicon carbide blank, resulting in a higher porosity for the adsorbent compared to the blank. During aluminizing, the adsorbent's capillary force on the molten aluminum is less than that of the silicon carbide blank, thus preventing the adsorbent from drawing out aluminum from the silicon carbide blank and only removing residual aluminum from the product surface.

[0038] In a specific embodiment, step S4 involves the following steps for the wet heat treatment: placing the aluminum silicon carbide blank that has undergone adsorption treatment in a high-temperature salt spray drying oven and storing it for 2-5 days at a relative humidity of 60-100RH% and a temperature of 80-150℃.

[0039] This invention employs the aforementioned damp heat treatment, utilizing the phenomenon that the reaction between water and aluminum carbide causes the composite material to pulverize. Moisture enters the secondary aluminum silicon carbide, and the aluminum carbide generated by the reaction rapidly hydrolyzes under high temperature and high humidity conditions, causing the secondary aluminum silicon carbide to pulverize. However, the aluminum silicon carbide body itself has a very low aluminum carbide content due to the peroxidation treatment, and the product has a high density, making it difficult for moisture to enter the interior, thus remaining unaffected. This achieves the effect of removing the secondary aluminum silicon carbide powder.

[0040] In a specific implementation, after the wet heat treatment in step S4, mechanical treatment can also be performed. The mechanical treatment mainly adopts processes such as sandblasting and sandpaper polishing. The processing amount of the above processes is relatively small, and the main purpose is to improve the surface finish.

[0041] The technical effects of the present invention will be described below with reference to specific embodiments.

[0042] Example 1

[0043] This embodiment provides a method for preparing aluminum silicon carbide composite material, which specifically includes the following steps: S1, preparing silicon carbide preform: using silicon carbide particles with a particle size of 10μm, a silicon carbide preform is prepared by injection molding and degreasing, and then the silicon carbide preform is oxidized to obtain an oxide layer. The specific steps of the oxidation treatment are: oxidizing at 950℃ for 6h to obtain an oxide layer with a thickness of 200nm.

[0044] S2, Aluminizing: The obtained silicon carbide billet is aluminized to obtain aluminum silicon carbide billet. The aluminum material used for aluminizing is cast aluminum, and the Si content in the cast aluminum is 10%.

[0045] S3, Residual Aluminum Adsorption: The aluminum silicon carbide blank obtained by aluminizing treatment in step S2 is buried in an adsorbent for adsorption treatment. The specific steps of the adsorption treatment are as follows: the aluminum silicon carbide blank is buried in the adsorbent, heated to 1000℃ under nitrogen atmosphere, and kept at that temperature for 3 hours.

[0046] The adsorbent includes a base powder and a penetration enhancer. The penetration enhancer accounts for 10% of the base powder content. The base powder is silicon carbide powder with a particle size of 15μm, and the ratio of silicon carbide powder, binder, dispersant and carbon source is 65:5:2:15. The penetration enhancer is fluorozirconate particles with a particle size of 1mm. The binder is hydroxypropyl methylcellulose. The dispersant is polyethylene glycol and ammonium acrylate. The carbon source is dextrin. The loose density of the adsorbent is less than the density of the silicon carbide blank. The preparation method of the adsorbent includes: first, mixing the raw material spherical graphite of the base powder and spray granulating it, then adding the penetration enhancer, and mixing it evenly with a V-type mixer.

[0047] S4. Post-treatment: The aluminum silicon carbide blanks that have undergone adsorption treatment are subjected to wet heat treatment in sequence to obtain aluminum silicon carbide composite materials. The specific steps of wet heat treatment are as follows: The aluminum silicon carbide blanks that have undergone adsorption treatment are placed in a high-temperature salt spray drying oven and placed for 2 days under the conditions of relative humidity of 100RH% and temperature of 100℃.

[0048] Figure 1 It is an untreated aluminum-silicon carbide composite material. Figure 2 The treated aluminum-silicon carbide composite material obtained in this embodiment clearly shows that... Figure 2 The surface of the treated aluminum-silicon carbide composite material is free of residual aluminum.

[0049] Example 2

[0050] This embodiment provides a method for preparing aluminum silicon carbide composite material, which specifically includes the following steps: S1, preparing silicon carbide blank: firstly, silicon carbide particles with a particle size of 20μm are oxidized. The specific steps of the oxidation treatment are: oxidizing at 1200℃ for 4h to obtain an oxide layer with a thickness of 300nm, and then using silicon carbide particles to prepare silicon carbide blank by 3D printing.

[0051] S2, Aluminizing: The obtained silicon carbide billet is aluminized to obtain aluminum silicon carbide billet. The aluminum material used for aluminizing is cast aluminum, and the Si content in the cast aluminum is 12%.

[0052] S3, Residual Aluminum Adsorption: The aluminum silicon carbide blank obtained by aluminizing treatment in step S2 is buried in an adsorbent for adsorption treatment. The specific steps of the adsorption treatment are as follows: the aluminum silicon carbide blank is buried in the adsorbent, and the temperature is raised to 1100℃ under nitrogen atmosphere and kept at the temperature for 2 hours.

[0053] The adsorbent includes a base powder and a penetration aid. The penetration aid accounts for 20% of the base powder content. The base powder is silicon carbide powder with a particle size of 20 μm, and the ratio of silicon carbide powder, binder, dispersant and carbon source is 70:8:1:20. The penetration aid is metallic magnesium particles with a particle size of 2 mm. The binder is polyethylene oxide. The dispersant is ammonium acrylate. The carbon source is obtained by mixing petroleum coke and sucrose in a 1:2 ratio. The loose density of the adsorbent is less than the density of the silicon carbide blank. The preparation method of the adsorbent includes: first mixing the raw material spherical graphite of the base powder and spray granulating it, then adding the penetration aid and mixing it evenly with a V-type mixer.

[0054] S4. Post-treatment: The aluminum silicon carbide blanks that have undergone adsorption treatment are subjected to wet heat treatment in sequence to obtain aluminum silicon carbide composite materials. The specific steps of wet heat treatment are as follows: The aluminum silicon carbide blanks that have undergone adsorption treatment are placed in a high-temperature salt spray drying oven and placed for 5 days under the conditions of relative humidity of 90RH% and temperature of 90℃.

[0055] Example 3

[0056] This embodiment provides a method for preparing aluminum silicon carbide composite material, which specifically includes the following steps: S1, preparing silicon carbide blank: firstly, silicon carbide particles with a particle size of 15μm are oxidized. The specific steps of the oxidation treatment are: oxidizing at 800℃ for 10h to obtain an oxide layer with a thickness of 800nm, and then using silicon carbide particles to prepare silicon carbide blank by 3D printing.

[0057] S2, Aluminizing: The obtained silicon carbide billet is aluminized to obtain aluminum silicon carbide billet. The aluminum material used for aluminizing is cast aluminum, and the Si content in the cast aluminum is 5%.

[0058] S3, Residual Aluminum Adsorption: The aluminum silicon carbide blank obtained by aluminizing treatment in step S2 is buried in an adsorbent for adsorption treatment. The specific steps of the adsorption treatment are as follows: the aluminum silicon carbide blank is buried in the adsorbent, heated to 800℃ under nitrogen atmosphere, and kept at that temperature for 8h.

[0059] The adsorbent includes a base powder and a penetration aid. The penetration aid accounts for 5% of the base powder content. The base powder is silicon carbide powder with a particle size of 0.5 μm, and the ratio of silicon carbide powder, binder, dispersant and carbon source is 50:1:1:10. The penetration aid is metallic magnesium particles with a particle size of 0.5 mm. The binder is polyvinyl alcohol, the dispersant is ammonia water, and the carbon source is obtained by mixing graphite powder and spray carbon black in a 1:2 ratio. The loose density of the adsorbent is less than the density of the silicon carbide blank. The preparation method of the adsorbent includes: first mixing the raw material spherical graphite of the base powder and spray granulating it, then adding the penetration aid and mixing it evenly with a V-type mixer.

[0060] S4. Post-treatment: The aluminum silicon carbide blanks that have undergone adsorption treatment are subjected to wet heat treatment in sequence to obtain aluminum silicon carbide composite materials. The specific steps of wet heat treatment are as follows: The aluminum silicon carbide blanks that have undergone adsorption treatment are placed in a high-temperature salt spray drying oven and placed for 2 days under the conditions of relative humidity of 60RH% and temperature of 80℃.

[0061] Example 4

[0062] This embodiment provides a method for preparing aluminum silicon carbide composite material, which specifically includes the following steps: S1, preparing silicon carbide preform: using silicon carbide particles with a particle size of 10μm to prepare silicon carbide preform by injection molding, and then oxidizing the silicon carbide preform to obtain an oxide layer. The specific steps of the oxidation treatment are: oxidizing at 1200℃ for 1h to obtain an oxide layer with a thickness of 150nm.

[0063] S2, Aluminizing: The obtained silicon carbide billet is aluminized to obtain aluminum silicon carbide billet. The aluminum material used for aluminizing is cast aluminum, and the Si content in the cast aluminum is 20%.

[0064] S3, Residual Aluminum Adsorption: The aluminum silicon carbide blank obtained by aluminizing treatment in step S2 is buried in an adsorbent for adsorption treatment. The specific steps of the adsorption treatment are as follows: the aluminum silicon carbide blank is buried in the adsorbent, heated to 1500℃ under nitrogen atmosphere, and kept at the temperature for 0.5h.

[0065] The adsorbent comprises a base powder and a penetration enhancer. The penetration enhancer accounts for 30% of the base powder content. The base powder is silicon carbide powder with a particle size of 100 μm, and the ratio of silicon carbide powder, binder, dispersant and carbon source is 80:10:1:20. The penetration enhancer is fluorozirconate particles with a particle size of 5 mm. The binder is a 1:1 mixture of polyvinyl alcohol and polyethylene oxide. The dispersant is a 1:1 mixture of polyethyleneimine and BYK. The carbon source is phenolic resin. The bulk density of the adsorbent is less than the density of the silicon carbide blank. The preparation method of the adsorbent includes: first, mixing the raw material spherical graphite of the base powder and spray granulating it, then adding the penetration enhancer, and mixing it evenly with a V-type mixer.

[0066] S4. Post-treatment: The aluminum silicon carbide blanks that have undergone adsorption treatment are subjected to wet heat treatment in sequence to obtain aluminum silicon carbide composite materials. The specific steps of wet heat treatment are as follows: The aluminum silicon carbide blanks that have undergone adsorption treatment are placed in a high-temperature salt spray drying oven and placed for 4 days under the conditions of relative humidity of 90RH% and temperature of 80℃.

[0067] Example 5

[0068] This embodiment provides a method for preparing aluminum silicon carbide composite material, which specifically includes the following steps: S1, preparing silicon carbide blank: firstly, silicon carbide particles with a particle size of 20μm are oxidized. The specific steps of the oxidation treatment are: oxidizing at 1200℃ for 4h to obtain an oxide layer with a thickness of 300nm, and then using silicon carbide particles to prepare silicon carbide blank by 3D printing.

[0069] S2, Aluminizing: The obtained silicon carbide billet is aluminized to obtain aluminum silicon carbide billet. The aluminum material used for aluminizing is cast aluminum, and the Si content in the cast aluminum is 18%.

[0070] S3, Residual Aluminum Adsorption: The aluminum silicon carbide blank obtained by aluminizing in step S2 is buried in an adsorbent for adsorption treatment. The specific steps of the adsorption treatment are as follows: the aluminum silicon carbide blank is buried in the adsorbent, heated to 1400℃ under nitrogen atmosphere, and kept at that temperature for 6 hours.

[0071] The adsorbent comprises a base powder and a penetration enhancer. The penetration enhancer accounts for 15% of the base powder content. The base powder is silicon carbide powder with a particle size of 80 μm, and the ratio of silicon carbide powder, binder, dispersant and carbon source is 50:1:1:10. The penetration enhancer is metallic magnesium particles with a particle size of 5 mm. The binder is polyethylene oxide. The dispersant is a mixture of glycerol and sodium hexaphosphate in a 1:1 ratio. The carbon source is graphite powder. The loose density of the adsorbent is less than the density of the silicon carbide blank. The preparation method of the adsorbent includes: first, mixing the raw material spherical graphite of the base powder and spray granulating it, then adding the penetration enhancer, and mixing it evenly with a V-type mixer.

[0072] S4. Post-treatment: The aluminum silicon carbide blanks that have undergone adsorption treatment are subjected to wet heat treatment in sequence to obtain aluminum silicon carbide composite materials. The specific steps of wet heat treatment are as follows: The aluminum silicon carbide blanks that have undergone adsorption treatment are placed in a high-temperature salt spray drying oven and placed for 3 days under the conditions of relative humidity of 100RH% and temperature of 140℃.

[0073] Comparative Example 1

[0074] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 3 is that step S1 in this comparative example does not include the oxidation treatment step of silicon carbide particles. The rest is the same as in Example 3, and will not be repeated here.

[0075] Comparative Example 2

[0076] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 1 is that step S1 in this comparative example does not include the oxidation treatment step of the silicon carbide preform. The rest is the same as in Example 1, and will not be repeated here.

[0077] Comparative Example 3

[0078] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference between this comparative example and Example 3 is that this comparative example does not include the adsorption treatment in step S3. The rest is the same as Example 3, and will not be repeated here.

[0079] Comparative Example 4

[0080] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 3 is that in step S3 of this comparative example, the adsorbent does not include a penetration aid. The rest is the same as in Example 3, and will not be repeated here.

[0081] Comparative Example 5

[0082] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 3 is that in step S3 of this comparative example, the base powder of the adsorbent does not include a binder. The rest is the same as in Example 3, and will not be repeated here.

[0083] Comparative Example 6

[0084] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 3 is that in step S3 of this comparative example, the base powder of the adsorbent does not include a dispersant. The rest is the same as in Example 3, and will not be repeated here.

[0085] Comparative Example 7

[0086] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 3 is that in step S3 of this comparative example, the base powder of the adsorbent does not include a carbon source. The rest is the same as in Example 3, and will not be repeated here.

[0087] Comparative Example 8

[0088] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 3 is that in step S3 of this comparative example, the ratio of silicon carbide powder, binder, dispersant and carbon source is 90:1:1:10. The other steps are the same as in Example 3 and will not be repeated here.

[0089] Comparative Example 9

[0090] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference from Example 3 is that in step S3 of this comparative example, the ratio of silicon carbide powder, binder, dispersant and carbon source is 40:1:1:10. The other steps are the same as in Example 3 and will not be repeated here.

[0091] Comparative Example 10

[0092] This comparative example provides a method for preparing an aluminum silicon carbide composite material. The only difference between this comparative example and Example 3 is that this comparative example does not include the wet heat treatment in step S4. The rest is the same as Example 3, and will not be repeated here.

[0093] The aluminum silicon carbide composite materials prepared in Examples 1-5 and Comparative Examples 1-10 were subjected to performance testing, and the test results are as follows:

[0094]

[0095]

[0096] As can be seen, by oxidizing the silicon carbide particles before preparing the silicon carbide blank, or by oxidizing the obtained silicon oxide blank, this invention can improve the wettability with the aluminum melt during aluminizing and reduce the harmful reaction between silicon carbide and aluminum to form aluminum carbide. This invention also allows the residual aluminum on the surface of the aluminum silicon carbide blank to penetrate into the powder of the adsorbent and form secondary aluminum silicon carbide by properly adjusting the adsorbent. The secondary aluminum silicon carbide is then removed by subsequent wet heat treatment, thereby removing the residual aluminum on the surface of the aluminum silicon carbide composite material, which facilitates the subsequent use and processing of the composite material.

[0097] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method of producing an aluminum silicon carbide composite material, characterized by, The preparation method specifically comprises the following steps: S1, preparing a silicon carbide blank: silicon carbide particles are prepared into a silicon carbide blank through a molding method; S2, aluminizing: the obtained silicon carbide blank is subjected to aluminizing treatment to obtain an aluminum silicon carbide blank; S3, residual aluminum adsorption: the aluminum silicon carbide blank obtained through the aluminizing treatment in step S2 is buried in an adsorbent for adsorption treatment; S4, post-treatment: the aluminum silicon carbide blank subjected to the adsorption treatment is subjected to wet heat treatment to obtain an aluminum silicon carbide composite material; In the step S1, the silicon carbide particles or the silicon carbide blank are further subjected to oxidation treatment to obtain an oxidation layer, and the specific steps of the oxidation treatment are as follows: oxidation at 800-120 ℃ for 1-10 h; the thickness of the oxidation layer is 150-1000 nm; In the step S3, the adsorbent comprises a base powder and a penetration aid, the content of the penetration aid is 5-30% of the content of the base powder, the base powder comprises silicon carbide powder, a binder, a dispersing agent and a carbon source, and the ratio of the silicon carbide powder, the binder, the dispersing agent and the carbon source is (50-80):(1-10):(1-5):(10-20); the penetration aid is magnesium particles or fluorozirconate particles, and the particle size of the penetration aid is 0.5-5 mm.

2. The method of claim 1, wherein the aluminum silicon carbide composite material is prepared by the steps of: mixing a silicon carbide powder and an aluminum powder; and sintering the mixed powder at a temperature of 600 to 800°C in a vacuum or an inert gas atmosphere. In the step S1, the molding method is selected from one of press molding, injection molding, grouting molding and 3D printing molding.

3. The method for preparing the aluminum-silicon carbide composite material as described in claim 1, characterized in that, In the step S2, the aluminum material used for the aluminizing is cast aluminum, and the Si content in the cast aluminum is 5-20%.

4. The method of claim 1, wherein the aluminum silicon carbide composite material is prepared by the steps of: mixing aluminum powder and silicon carbide powder; and sintering the mixture at a temperature of 1,000°C to 1,500°C in a vacuum or an inert gas atmosphere. The particle size of the silicon carbide powder is 0.5-100 μm, the binder is selected from at least one of polyvinyl alcohol, polyethylene oxide and hydroxypropyl methyl cellulose, the dispersing agent is selected from at least one of ammonia water, glycerol, polyethylene glycol, sodium hexametaphosphate, ammonium acrylate, glycerol, quaternary ammonium salt, polyacrylate, polyethyleneimine and BYK, and the carbon source is selected from at least one of petroleum coke, graphite powder, spray carbon black, dextrin, sugar and phenolic resin.

5. The method of claim 1, wherein the aluminum silicon carbide composite material is prepared by the steps of: mixing a silicon carbide powder and an aluminum powder; and sintering the mixture at a temperature of 600 to 800°C in a vacuum or an inert gas atmosphere. 5 In the step S3, the apparent density of the adsorbent is less than the density of the silicon carbide blank.

6. The method of claim 1, wherein the aluminum silicon carbide composite material is prepared by the steps of: mixing a silicon carbide powder and an aluminum powder; and sintering the mixture at a temperature of 600 to 800°C in a vacuum or an inert gas atmosphere. 5 In the step S3, the specific steps of the adsorption treatment are as follows: the aluminum silicon carbide blank is buried in the adsorbent, heated to 800-1500 ℃ under a nitrogen atmosphere, and kept at the temperature for 0.5-8 h.

7. The method of claim 1, wherein the aluminum silicon carbide composite material is prepared by the steps of: mixing aluminum powder and silicon carbide powder; and sintering the mixture at a temperature of 1,000°C to 1,500°C in a vacuum or an inert gas atmosphere. In the step S4, the specific steps of the wet heat treatment are as follows: the aluminum silicon carbide blank subjected to the adsorption treatment is placed in a high-temperature salt mist drying box, and placed at a relative humidity of 60-100 RH% and a temperature of 80-150 ℃ for 2-5 days.

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