A method for producing an aluminum and silicon carbide composite powder for additive manufacturing

Abstract

A preparation method of an aluminum and silicon carbide composite powder for additive manufacturing, comprising the following steps: (1) high-temperature oxidation treatment of silicon carbide powder; (2) immersion of the silicon carbide powder into a NaOH solution or a NaCO3 solution and ultrasonic cleaning; (3) immersion of the silicon carbide powder into an HF acid solution and ultrasonic vibration; (4) immersion of the silicon carbide powder into a mixed activation liquid of ferrous nitrate and sodium borohydride and ultrasonic soaking; (5) chemical copper plating of the silicon carbide powder; (6) cleaning; (7) chemical nickel plating; (8) rinsing of the copper-plated and nickel-plated silicon carbide powder with deionized water; (9) mixing of the copper-plated and nickel-plated silicon carbide powder with aluminum powder, drying, and obtaining the aluminum and silicon carbide composite powder for additive manufacturing. The present application can reduce the printing defects of SLM-prepared SiC P / Al composite material components, effectively inhibit the generation of Al3C4, and improve the mechanical properties, so as to meet the demand of aerospace precision components.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing, and in particular to a method for preparing an aluminum and silicon carbide composite powder for additive manufacturing. Background Technology

[0002] SiC P SiC / Al composites, with their superior properties such as low density and high stiffness, have demonstrated an irreplaceable role in key core components of next-generation equipment, providing a fundamental guarantee for equipment upgrades. However, as a typical difficult-to-machine material, SiC... P The reinforcing effect of SiC particles in Al materials enhances the hardness and strength of the matrix material, but also negatively impacts machining. Currently, complex structures and thin-walled parts of aluminum-based silicon carbide composites for aerospace applications are typically fabricated using rods or sheets, resulting in excessive machining allowances that severely affect processing efficiency. Furthermore, defects such as deformation and chipping are prone to occur during composite material processing, leading to part scrap. The high processing cost, low processing efficiency, and difficulty in guaranteeing processing accuracy of this material have hindered its widespread application. Therefore, research on efficient and high-precision structural design and near-net-shape forming technology for complex aluminum-based silicon carbide composite materials is urgently needed.

[0003] In recent years, with the rapid development of 3D printing additive manufacturing technology, SiC P New ideas and new technologies for the design and fabrication of SiC / Al composite components are attracting increasing attention. This includes the use of additive manufacturing technology to form SiC / Al composite components. P SiC / Al composite materials have significant advantages and broad application prospects in additive manufacturing technology. P The preparation of SiC / Al composite materials mainly involves selective laser melting (SLM) and selective laser sintering (SLS) to produce components with a volume fraction of less than 30%. However, these techniques are currently in the laboratory stage, with no physical prototypes available. This is primarily due to the poor interfacial wettability between silicon carbide and aluminum alloy, which easily leads to defects such as voids and cracks during the printing process. Surface modification can improve the wettability between silicon carbide and aluminum alloy, thereby enhancing the additive manufacturing performance of SiC / Al composites. P Compactness and properties of Al composite components.

[0004] Currently, selective laser melting (SLM) technology is used to manufacture SiC. PFor Al composite components, silicon carbide pre-oxidation and electroless copper or nickel plating are commonly used to improve interfacial wettability. For example, Chinese patent application No. 202210428198.8 discloses a SiC-induced multiphase reinforced aluminum matrix composite material and its preparation method. This method involves producing a dense amorphous / microcrystalline SiO2 layer in situ on the SiC surface through high-temperature oxidation, resulting in a ceramic-ceramic interface. However, this bonding strength is lower than that of metal-metallurgical bonding, and it primarily targets composite materials with a SiC content of less than 10%. Such composites have an elastic modulus below 90 GPa, making it difficult to meet the comprehensive mechanical performance requirements (tensile strength ≥ 400 MPa, elastic modulus ≥ 100 GPa) for precision aerospace structural components. Furthermore, higher SiC content increases the difficulty of additive manufacturing. Electroless copper / nickel plating, on the other hand, deposits a metal or alloy layer on the SiC surface through a redox reaction, achieving metallurgical bonding and significantly improving the material's mechanical properties. Current technologies only employ a single metal plating layer. For example, Chinese patent application No. 202311605178.4 discloses a method for preparing aluminum-based composite materials, aluminum-based composite materials, and their applications. It uses a chemical copper plating method, where Cu preferentially reacts with Al to form the Al2Cu phase, suppressing the formation of the brittle Al3C4 phase and improving performance. However, in additive manufacturing processes, copper has high laser reflectivity and generates a large heat of reaction with aluminum, which can easily lead to spatter, pores, or excessive growth of interfacial compounds, resulting in an excessively thick Al2Cu layer that affects performance. Although silicon carbide copper plating can effectively improve interfacial bonding strength, it requires high-performance laser forming equipment and precise control of laser parameters, making production difficult. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for preparing aluminum and silicon carbide composite powder for additive manufacturing, wherein the volume fraction of copper-plated and nickel-plated silicon carbide powder is 10%~30%; the copper-plated and nickel-plated silicon carbide powder and aluminum powder are mixed for SLM to prepare aluminum-based silicon carbide composite materials, which combines the high interfacial bonding strength of copper and the stability of nickel, and can obtain aluminum-based silicon carbide composite material components with the best performance.

[0006] The technical solution adopted by this invention to solve its technical problem is a method for preparing aluminum and silicon carbide composite powder for additive manufacturing, comprising the following steps:

[0007] (1) The silicon carbide powder is subjected to high-temperature oxidation treatment;

[0008] The purpose of high-temperature oxidation treatment is to remove free carbon and organic matter from silicon carbide powder;

[0009] (2) Immerse the silicon carbide powder treated by high temperature oxidation in step (1) into NaOH solution or NaCO3 solution, ultrasonically clean for 30-60 minutes (mainly to remove surface oil), and ultrasonically clean with deionized water;

[0010] In existing technologies, surface impurities are usually removed by cleaning with alkaline and acidic solutions. In this solution, high-temperature treatment is first used to completely decompose free carbon and organic matter on the surface, thus avoiding a decrease in adhesion due to carbon contamination during subsequent plating processes.

[0011] (3) Immerse the silicon carbide powder treated in step (2) in HF acid solution, ultrasonically vibrate for 20-35 minutes, and then ultrasonically clean it with deionized water;

[0012] In the prior art, nitric acid solution is generally used to roughen silicon carbide. Silicon carbide has high stability, and nitric acid is difficult to completely activate the surface of silicon carbide, which affects the adhesion of the coating. In this invention, HF acid solution is used to corrode the silicon oxide layer on the surface of silicon carbide, forming micron-level pits to achieve a roughening effect and improve the adhesion of the coating. With the help of ultrasound, it is beneficial to uniformly roughen the silicon carbide powder.

[0013] In step (3), the silicon carbide surface is roughened with acid to give the silicon carbide surface micro-roughness, thereby increasing surface activity and micro-roughness.

[0014] (4) Immerse the silicon carbide powder treated in step (3) in a mixed activation solution of ferrous nitrate and sodium borohydride, soak it under ultrasonic action for 10-30 minutes, and then clean it with anhydrous ethanol by ultrasonication.

[0015] Existing technologies often employ palladium salts or stannous chloride for activation, while the method of this invention uses a ferrous nitrate + sodium borohydride system: sodium borohydride (NaBH4) acts as a strong reducing agent to reduce Fe²⁺. + The iron is reduced to Fe, and nano-iron particles are deposited on the silicon carbide surface to form catalytic active sites. This avoids the high cost of the precious metal palladium and is more suitable for large-scale production.

[0016] Step (4) involves sensitization and activation treatment to enable the metal layer to be reduced.

[0017] (5) Immerse the silicon carbide powder treated in step (4) into the chemical copper plating bath and plate it for 20-30 minutes under ultrasonic stirring to obtain copper-plated silicon carbide powder.

[0018] (6) The copper-plated silicon carbide powder obtained in step (5) is immediately washed repeatedly with deionized water until the pH is 7±0.5; the purpose of this cleaning step is to remove surface residues.

[0019] (7) Immerse the copper-plated silicon carbide powder treated in step (6) into the electroless nickel plating bath, and ultrasonically stir for 30-60 minutes to obtain copper-plated and nickel-plated silicon carbide powder.

[0020] (8) Rinse the copper-plated and nickel-plated silicon carbide powder obtained in step (7) repeatedly with deionized water and dry it in a drying oven;

[0021] (9) Mix the copper-plated and nickel-plated silicon carbide powder treated in step (8) with aluminum powder evenly, and dry under vacuum to obtain aluminum and silicon carbide composite powder for additive manufacturing.

[0022] Furthermore, in step (1), the particle size range of silicon carbide powder is 10~50μm. The oxidation temperature of the high-temperature oxidation treatment is 700-900℃, and the holding time of the high-temperature oxidation treatment is 2-3 hours. Studies have shown that high-temperature treatment can completely separate free carbon and organic matter on the surface, avoiding the decrease in adhesion due to carbon contamination during subsequent plating. If the temperature is too low, organic matter cannot be effectively removed, resulting in poor adhesion of the thick plating layer. If the temperature is too high, an excessive SiO2 layer will be formed on the silicon carbide surface to encapsulate carbon impurities, reducing the carbon removal rate. If the particle size of silicon carbide powder is too small, the powder is prone to agglomeration and material segregation, resulting in poor powder flowability and affecting the powder spreading quality. If the particles are too coarse, the particle distribution is uneven, stress concentration is likely to occur, and the material density is low.

[0023] Furthermore, in step (2), the mass concentration of the NaOH solution or NaCO3 solution is 8-12% (preferably 10%). Studies have shown that if the concentration of the NaOH solution or NaCO3 solution is too low, the cleaning time is too long, the efficiency is low, and the cleaning is easily incomplete; if the concentration is too high, it is easy to cause the material to be ablated, and the high concentration of alkaline solution adheres to the material surface and is difficult to clean.

[0024] Furthermore, in step (3), the mass concentration of the HF acid solution is 4-6% (preferably 5%). Studies have shown that if the concentration of the HF acid solution is too low, its ability to dissolve the oxide layer and impurities on the silicon carbide surface is insufficient, resulting in inadequate surface etching and affecting the adhesion of the coating; if the concentration is too high, the etching rate is too fast, forming deep pits or microcracks on the silicon carbide surface, which become stress concentration points.

[0025] Furthermore, in step (4), the mass concentration of ferrous nitrate in the mixed activation solution of ferrous nitrate and sodium borohydride is 4-6 g / L (preferably 5 g / L), and the mass concentration of sodium borohydride is 2-4 g / L (preferably 3 g / L). Studies have shown that if the concentrations of ferrous nitrate and sodium borohydride in the mixed activation solution are too high, over-corrosion is likely to occur, and the corrosion time will be difficult to control. If the concentrations are too low, corrosion may not be complete, and the reaction may be too slow.

[0026] Furthermore, in step (5), the chemical copper plating bath solution is composed of copper sulfate (5-15) g / L + complexing agent + reducing agent + stabilizer + deionized water (general copper plating bath solution), with a pH value of 11-13 and a temperature of 30-50℃.

[0027] Furthermore, in step (7), the electroless nickel plating bath is composed of nickel sulfate (10-20) g / L + complexing agent + reducing agent + buffer + deionized water (general nickel plating bath), with a pH value of 4-6 and a plating temperature of 50-70℃.

[0028] Furthermore, in step (9), the aluminum powder particle size range is 15~53μm. When copper-plated and nickel-plated silicon carbide powder is mixed with aluminum powder, the volume percentage of aluminum powder is 70%~90%, and the volume percentage of copper-plated and nickel-plated silicon carbide powder is 10%~30%. The preferred method for uniform mixing is ball milling under argon protection. Drying is preferably done in a vacuum oven. Studies have shown that if the aluminum powder is too fine, it will have poor flowability and easily form agglomerates; if it is too coarse, it will easily produce defects such as pores and incomplete fusion, resulting in poor interlayer bonding.

[0029] Furthermore, in step (9), the vacuum degree of vacuum drying is ≤0.02MPa and the temperature is 60-70℃.

[0030] Further, in step (9), aluminum-based silicon carbide composite powder for additive manufacturing is used to form an aluminum-based silicon carbide composite material. The specific manufacturing method is selective laser melting, with the following process parameters: substrate preheating temperature of 100~200℃, laser power of 280~360W, powder layer thickness of 25μm~45μm, scanning speed of 1000mm / s~1400mm / s, and scanning spacing of 90μm~130μm. After printing, the component is subjected to a 280℃ solution strengthening treatment after the support is removed.

[0031] The purpose of this invention, which employs copper plating followed by nickel plating, is to protect the copper layer from reaction and prevent the formation of harmful substances such as Al3C. 4。 Pretreatment before copper or nickel plating is essential; otherwise, the adhesion of the plating layer will be poor.

[0032] This invention employs a chemical copper and nickel plating composite coating on silicon carbide powder to ensure the density of aluminum-based silicon carbide composite materials while improving their mechanical properties. The aluminum-based silicon carbide composite materials prepared by this method show significantly improved density and mechanical properties.

[0033] The present invention discloses a method for preparing aluminum-based silicon carbide composite powder for additive manufacturing, which involves subjecting silicon carbide powder to high-temperature treatment and chemically depositing a Cu / Ni composite coating, then uniformly mixing it with aluminum powder and selectively laser melting to form SiC. P / Al composite material components achieve high density and high mechanical properties.

[0034] The method for preparing aluminum-based silicon carbide composite powder for additive manufacturing of the present invention can reduce the amount of material processed by SLM to prepare SiC. P The printing defects of Al composite components are effectively suppressed, the formation of Al3C4 is inhibited, and the mechanical properties are improved to meet the requirements of precision aerospace components.

[0035] This invention employs electroless nickel plating to improve the wettability between Al and SiC in additive manufacturing, thereby enhancing the wettability of aluminum-based silicon carbide composites. The nickel layer exhibits superior stability compared to copper, providing durable protection against harmful interfacial reactions and offering high hardness and wear resistance; however, its densification-promoting effect is not as strong as copper. Therefore, this invention combines the advantages of both nickel and copper layers to improve the wettability of additively manufactured SiC... P This invention improves the density and mechanical properties of Al composite materials while persistently preventing harmful interfacial reactions. Through this invention, high-performance aluminum-based silicon carbide composite material components can be formed using SLM molding. Attached Figure Description

[0036] Figure 1 The TEM image of the product printed using the aluminum and silicon carbide composite powder (copper-plated and nickel-plated silicon carbide powder) obtained in Example 1 of the present invention.

[0037] Figure 2 The stress-strain curves of SLM-formed aluminum-based silicon carbide products in Example 1 of the present invention, including copper-plated and nickel-plated silicon carbide powder, unplated silicon carbide powder in Comparative Example 1, and copper-plated silicon carbide powder in Comparative Example 2 are shown.

[0038] Figure 3 This is a photograph of a product printed using the aluminum and silicon carbide composite powder (copper-plated and nickel-plated silicon carbide powder) obtained in Example 1 of the present invention. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0040] Example 1

[0041] A method for preparing an aluminum-silicon carbide composite powder for additive manufacturing includes the following steps:

[0042] (1) The silicon carbide powder is subjected to high-temperature oxidation treatment to remove free carbon and organic matter from the silicon carbide powder;

[0043] In step (1), the particle size range of silicon carbide powder is 10~50μm. The oxidation temperature of the high-temperature oxidation treatment is 900℃, and the holding time of the high-temperature oxidation treatment is 3 hours.

[0044] (2) Immerse the silicon carbide powder treated by high temperature oxidation in step (1) into NaOH solution, ultrasonically clean for 30 minutes (mainly to remove surface oil), and ultrasonically clean with deionized water;

[0045] In step (2), the mass concentration of the NaOH solution is 10%.

[0046] (3) Immerse the silicon carbide powder treated in step (2) in HF acid solution, ultrasonically vibrate for 35 min, and then ultrasonically clean it with deionized water until the pH value is 7.

[0047] In step (3), the silicon carbide surface is roughened with acid to give the silicon carbide surface micro-roughness, thereby increasing surface activity and micro-roughness.

[0048] In step (3), the mass concentration of the HF acid solution is 5%.

[0049] (4) Immerse the silicon carbide powder treated in step (3) in a mixed activation solution of ferrous nitrate and sodium borohydride, soak it under ultrasonic action for 20 minutes, and then clean it with anhydrous ethanol by ultrasonication.

[0050] Step (4) involves sensitization and activation treatment to enable the metal layer to be reduced.

[0051] In step (4), the mass concentration of ferrous nitrate in the mixed activation solution of ferrous nitrate and sodium borohydride is 5 g / L, and the mass concentration of sodium borohydride is 3 g / L.

[0052] (5) Immerse the silicon carbide powder treated in step (4) into the chemical copper plating bath and plate it for 20 minutes under ultrasonic stirring to obtain copper-plated silicon carbide powder.

[0053] In step (5), the chemical copper plating bath solution is a general copper plating bath solution: copper sulfate 10g / L, complexing agent is ethylenediaminetetraacetic acid 15g / L and potassium sodium tartrate 10g / L, reducing agent is formaldehyde 1.5wt%, stabilizer is methanol 0.8wt%, deionized water, pH value is 12, and temperature is 50℃.

[0054] (6) The copper-plated silicon carbide powder obtained in step (5) is immediately washed repeatedly with deionized water until the pH is 7±0.5; the purpose of this cleaning step is to remove surface residues.

[0055] (7) Immerse the copper-plated silicon carbide powder treated in step (6) into the electroless nickel plating bath, and ultrasonically stir for 30 minutes to obtain copper-plated and nickel-plated silicon carbide powder.

[0056] In step (7), the electroless nickel plating bath is a general nickel plating bath: nickel sulfate 15g / L, complexing agent citric acid 10g / L, reducing agent sodium hypophosphite 15g / L, buffer sodium acetate 12g / L, deionized water, pH value 5, and plating temperature 60℃.

[0057] (8) Rinse the copper-plated and nickel-plated silicon carbide powder obtained in step (7) repeatedly with deionized water and dry it in a drying oven;

[0058] (9) Mix the copper-plated and nickel-plated silicon carbide powder and aluminum powder after step (8) evenly, and dry them under vacuum to obtain a composite powder of aluminum and silicon carbide for additive manufacturing.

[0059] In step (9), the aluminum powder particle size ranges from 15 to 53 μm. When copper-plated and nickel-plated silicon carbide powder is mixed with aluminum powder, the volume fraction of aluminum powder is 90%, and the volume percentage of copper-plated and nickel-plated silicon carbide powder is 10%. The mixing is achieved by ball milling under argon protection. Drying is performed using a vacuum oven.

[0060] In step (9), the vacuum degree of vacuum drying is 0.02MPa and the temperature is 60℃.

[0061] In step (9), aluminum-based silicon carbide composite powder for additive manufacturing is used to form an aluminum-based silicon carbide composite material. The specific manufacturing method is selective laser melting, with the following process parameters: substrate preheating temperature 200℃, laser power 360W, powder layer thickness 45μm, scanning speed 1400mm / s, and scanning spacing 130μm. After printing, the component is subjected to solution strengthening treatment at 280℃ after the support is removed.

[0062] The aluminum-based silicon carbide component manufactured by the above method in this embodiment has a tensile strength of 401 MPa and a density of 99.6%.

[0063] Figure 1 The image shows a TEM image of a product printed using the aluminum and silicon carbide composite powder (copper-plated and nickel-plated silicon carbide powder) obtained in Example 1 of this invention. Analysis shows that only the Al3SiC4 reinforcing phase is present at the aluminum and silicon carbide interface, and no harmful brittle phase Al3C4 is observed.

[0064] Figure 3 This is a photograph of a product printed using the aluminum and silicon carbide composite powder (copper-plated and nickel-plated silicon carbide powder) obtained in Example 1 of the present invention.

[0065] Example 2

[0066] A method for preparing an aluminum-silicon carbide composite powder for additive manufacturing includes the following steps:

[0067] (1) The silicon carbide powder is subjected to high-temperature oxidation treatment to remove free carbon and organic matter from the silicon carbide powder;

[0068] In step (1), the particle size range of silicon carbide powder is 10~50μm. The oxidation temperature of the high-temperature oxidation treatment is 900℃, and the holding time of the high-temperature oxidation treatment is 2 hours.

[0069] (2) Immerse the silicon carbide powder treated by high temperature oxidation in step (1) into NaOH solution, ultrasonically clean for 60 min (mainly to remove surface oil), and ultrasonically clean with deionized water;

[0070] In step (2), the mass concentration of the NaOH solution is 10%.

[0071] (3) Immerse the silicon carbide powder treated in step (2) in HF acid solution, ultrasonically vibrate for 20 min, and then ultrasonically clean it with deionized water;

[0072] In step (3), the silicon carbide surface is roughened with acid to give the silicon carbide surface micro-roughness, thereby increasing surface activity and micro-roughness.

[0073] In step (3), the mass concentration of the HF acid solution is 5%.

[0074] (4) Immerse the silicon carbide powder treated in step (3) in a mixed activation solution of ferrous nitrate and sodium borohydride, soak it under ultrasonic action for 20 minutes, and then clean it with anhydrous ethanol by ultrasonication.

[0075] Step (4) involves sensitization and activation treatment to enable the metal layer to be reduced.

[0076] In step (4), the mass concentration of ferrous nitrate in the mixed activation solution of ferrous nitrate and sodium borohydride is 5 g / L, and the mass concentration of sodium borohydride is 3 g / L.

[0077] (5) Immerse the silicon carbide powder treated in step (4) into the chemical copper plating bath and plate it for 20 minutes under ultrasonic stirring to obtain copper-plated silicon carbide powder.

[0078] In step (5), the chemical copper plating bath solution is a general copper plating bath solution: copper sulfate 10g / L, complexing agent ethylenediaminetetraacetic acid 15g / L, potassium sodium tartrate 10g / L, reducing agent formaldehyde 1.5wt%, stabilizer methanol 0.8wt%, deionized water, pH value 12, temperature 50℃.

[0079] (6) The copper-plated silicon carbide powder obtained in step (5) is immediately washed repeatedly with deionized water until the pH is 7±0.5; the purpose of this cleaning step is to remove surface residues.

[0080] (7) Immerse the copper-plated silicon carbide powder treated in step (6) into the electroless nickel plating bath, and ultrasonically stir for 30 minutes to obtain copper-plated and nickel-plated silicon carbide powder.

[0081] In step (7), the electroless nickel plating bath is a general nickel plating bath: nickel sulfate 15g / L, complexing agent citric acid 10g / L, reducing agent sodium hypophosphite 15g / L, buffer sodium acetate 12g / L, deionized water, pH value 5, and plating temperature 60℃.

[0082] (8) Rinse the copper-plated and nickel-plated silicon carbide powder obtained in step (7) repeatedly with deionized water and dry it in a drying oven;

[0083] (9) Mix the copper-plated and nickel-plated silicon carbide powder treated in step (8) with aluminum powder evenly, and dry under vacuum to obtain aluminum and silicon carbide composite powder for additive manufacturing.

[0084] In step (9), the aluminum powder particle size ranges from 15 to 53 μm. When copper-plated and nickel-plated silicon carbide powder is mixed with aluminum powder, the volume fraction of aluminum powder is 70%, and the volume fraction of copper-plated and nickel-plated silicon carbide powder is 30%. The mixing is achieved by ball milling under argon protection. Drying is performed using a vacuum oven.

[0085] In step (9), the vacuum degree of vacuum drying is 0.02MPa and the temperature is 60℃.

[0086] In step (9), aluminum-based silicon carbide composite powder for additive manufacturing is used to form an aluminum-based silicon carbide composite material. The specific manufacturing method is selective laser melting, with the following process parameters: substrate preheating temperature of 100℃, laser power of 360W, powder layer thickness of 45μm, scanning speed of 1400mm / s, and scanning spacing of 130μm. After printing, the component is subjected to solution strengthening treatment at 280℃ after the support is removed.

[0087] The 30% volume fraction aluminum-based silicon carbide composite material prepared by the above method has an elastic modulus of 121 GPa and a density of 99.1%.

[0088] Comparative Example 1 (Uncoated)

[0089] This comparative example includes the following steps:

[0090] (1) Weigh out silicon carbide powder with a particle size range of 10~50μm and aluminum powder with a particle size range of 15~53μm and mix them evenly, wherein the volume fraction of aluminum powder is 90% and the volume fraction of silicon carbide powder is 10%, and dry under vacuum to obtain composite powder of aluminum and silicon carbide for additive manufacturing; the vacuum degree of vacuum drying is 0.02MPa and the temperature is 60℃.

[0091] (2) Aluminum-based silicon carbide composite material was obtained by molding aluminum and silicon carbide composite powder for additive manufacturing. The specific molding method was selective laser melting molding, with the following process parameters: substrate preheating temperature 200℃, laser power 360W, powder layer thickness 45μm, scanning speed 1400mm / s, and scanning spacing 130μm. After printing, the component was subjected to solution strengthening treatment at 280℃ after the support was removed.

[0092] The aluminum-based silicon carbide composite material obtained by proportional molding has a tensile strength of 166.2 MPa and a density of 94.12%.

[0093] Comparative Example 2

[0094] This comparative example includes the following steps:

[0095] (1) Silicon carbide powder with a particle size range of 10~50μm was subjected to high-temperature oxidation treatment at a temperature of 1000℃ and a holding time of 3h, and then cooled with the furnace.

[0096] (2) Weigh out the silicon carbide powder from step (1) and mix it evenly with aluminum powder with a particle size range of 15~53μm, wherein the volume fraction of aluminum powder is 90% and the volume fraction of silicon carbide powder is 10%, and vacuum dry it to obtain a composite powder of aluminum and silicon carbide for additive manufacturing; the vacuum degree of vacuum drying is 0.02MPa and the temperature is 60℃.

[0097] (3) Aluminum-based silicon carbide composite material was obtained by molding aluminum and silicon carbide composite powder for additive manufacturing. The specific molding method was selective laser melting, with the following process parameters: substrate preheating temperature 200℃, laser power 360W, powder layer thickness 45μm, scanning speed 1400mm / s, and scanning spacing 130μm. After printing, the component was subjected to solution strengthening treatment at 280℃ after the support was removed.

[0098] The aluminum-based silicon carbide with a volume fraction of 10% prepared by the above method has a tensile strength of 364 MPa and a density of 98.9%.

[0099] Comparative Example 3

[0100] This comparative example includes the following steps:

[0101] (1) Silicon carbide powder was coated according to the method of Example 1 in the patent "A method for preparing aluminum-based composite material, aluminum-based composite material and its application" (application number 202311605178.4) (the wetting angle is small and the sphericity is high in Example 1, and the coating is carried out accordingly).

[0102] (2) Weigh out the silicon carbide powder from step (1) and mix it with aluminum powder with a particle size range of 15~53μm. The volume fraction of aluminum powder is 90% and the volume fraction of silicon carbide powder is 10%. Vacuum dry to obtain composite powder of aluminum and silicon carbide for additive manufacturing. The vacuum degree of vacuum drying is 0.02MPa and the temperature is 60℃.

[0103] (3) Aluminum-based silicon carbide composite material was obtained by molding aluminum and silicon carbide composite powder for additive manufacturing. The specific molding method was selective laser melting, with the following process parameters: substrate preheating temperature 200℃, laser power 360W, powder layer thickness 45μm, scanning speed 1400mm / s, and scanning spacing 130μm. After printing, the component was subjected to solution strengthening treatment at 280℃ after the support was removed.

[0104] The aluminum-based silicon carbide composite material prepared by the above method has a tensile strength of 377.55 MPa and a density of 99.4%.

[0105] It is evident that the copper-nickel plated product exhibits superior performance and density compared to copper-plated products in the embodiments of this invention. Furthermore, the use of copper-plated powder in the SLM process carries significant risks, requiring stringent equipment requirements and precise process control. The preparation method of aluminum-based silicon carbide composite powder for additive manufacturing in this invention can reduce the processing steps required for SiC in SLM. P The printing defects of Al composite components are effectively suppressed, the formation of Al3C4 is inhibited, and the mechanical properties are improved to meet the requirements of precision aerospace components.

[0106] Figure 2 This is a tensile strength curve of the SLM-formed aluminum-based silicon carbide products from Example 1 (copper-plated and nickel-plated), Comparative Example 1 (unplated silicon carbide), and Comparative Example 3 (copper-plated silicon carbide). The tensile strength was tested according to GB / T228.1-2021 "Metallic Materials - Tensile Testing Methods". From... Figure 2 It can be seen that the tensile strength of silicon carbide copper-nickel plated products is higher than that of copper-plated and unplated products.

Claims

1. A method for preparing an aluminum and silicon carbide composite powder for additive manufacturing, characterized in that, Includes the following steps: (1) The silicon carbide powder is subjected to high-temperature oxidation treatment; The oxidation temperature for high-temperature oxidation treatment is 700-900℃; (2) Immerse the silicon carbide powder treated by high temperature oxidation in step (1) into NaOH solution or NaCO3 solution, ultrasonically clean for 30-60 min, and ultrasonically clean with deionized water; (3) Immerse the silicon carbide powder treated in step (2) in HF acid solution, ultrasonically vibrate for 20-35 minutes, and then ultrasonically clean it with deionized water; (4) Immerse the silicon carbide powder treated in step (3) in a mixed activation solution of ferrous nitrate and sodium borohydride, soak it under ultrasonic action for 10-30 minutes, and then clean it with anhydrous ethanol by ultrasonication. (5) Immerse the silicon carbide powder treated in step (4) into the chemical copper plating bath and plate it for 20-30 minutes under ultrasonic stirring to obtain copper-plated silicon carbide powder. (6) The copper-plated silicon carbide powder obtained in step (5) is immediately washed repeatedly with deionized water until the pH is 7±0.5; (7) Immerse the copper-plated silicon carbide powder treated in step (6) into the electroless nickel plating bath, and ultrasonically stir for 30-60 minutes to obtain copper-plated and nickel-plated silicon carbide powder. (8) Rinse the copper-plated and nickel-plated silicon carbide powder obtained in step (7) repeatedly with deionized water and dry it in a drying oven; (9) Mix the copper-plated and nickel-plated silicon carbide powder treated in step (8) with aluminum powder evenly, and dry under vacuum to obtain aluminum and silicon carbide composite powder for additive manufacturing.

2. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1, characterized in that, In step (1), the particle size range of silicon carbide powder is 10~50μm.

3. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1 or 2, characterized in that, In step (1), the holding time for high-temperature oxidation treatment is 2-3 hours.

4. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1 or 2, characterized in that, In step (2), the mass concentration of the NaOH solution or NaCO3 solution is 8-12%.

5. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1 or 2, characterized in that, In step (3), the mass concentration of the HF acid solution is 4-6%.

6. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1 or 2, characterized in that, In step (4), the mass concentration of ferrous nitrate in the mixed activation solution of ferrous nitrate and sodium borohydride is 4-6 g / L, and the mass concentration of sodium borohydride is 2-4 g / L.

7. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1 or 2, characterized in that, In step (5), electroless copper plating is performed at a pH of 11-13 and a temperature of 30-50℃; and / or, in step (7), electroless nickel plating is performed at a pH of 4-6 and a plating temperature of 50-70℃.

8. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1 or 2, characterized in that, In step (9), the aluminum powder particle size range is 15~53μm.

9. The method for preparing aluminum and silicon carbide composite powder for additive manufacturing according to claim 1 or 2, characterized in that, In step (9), when copper-plated and nickel-plated silicon carbide powder is mixed with aluminum powder, the volume fraction of aluminum powder is 70%~90% and the volume fraction of copper-plated and nickel-plated silicon carbide powder is 10%~30%; and / or, the method of uniform mixing is ball milling under argon protection; and / or, drying is done in a vacuum oven; and / or, the vacuum degree of vacuum drying is ≤0.02MPa and the temperature is 60-70℃.

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