Treatment method for silicon carbide, and silicon-carbide-reinforced aluminum-based composite material
By treating silicon carbide particles with high-concentration hydrofluoric acid, their surface properties are altered, improving the interfacial bonding with the aluminum alloy matrix. This solves the problems of insufficient strength and thermal diffusivity in silicon carbide-reinforced aluminum matrix composites, thereby enhancing the overall performance of the material.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- NORTH CHINA UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-07
Smart Images
Figure PCTCN2024130574-APPB-I100001 
Figure PCTCN2024130574-APPB-I100002 
Figure PCTCN2024130574-APPB-I100003
Abstract
Description
A silicon carbide treatment method and silicon carbide reinforced aluminum matrix composite material Technical Field
[0001] This invention relates to the field of metal matrix composites, and more particularly to a silicon carbide treatment method and a silicon carbide reinforced aluminum matrix composite. Background Technology
[0002] The low expansion, high specific modulus, high thermal conductivity, and high resonant frequency of high-volume-fraction ceramic particle-reinforced aluminum matrix composites enable them to simultaneously possess excellent structural load-bearing capacity, superior thermal control, and unique anti-resonance capabilities. Taking high-volume-fraction (55%) silicon carbide particle-reinforced aluminum matrix composites as an example, their specific modulus can reach three times that of aluminum alloys and titanium alloys, while their coefficient of thermal expansion is less than 40% of that of aluminum alloys, even lower than that of titanium alloys. Their average resonant frequency is more than 60% higher than that of aluminum, titanium, and steel—three commonly used metal structural materials—and their thermal conductivity is far superior to that of aluminum alloys. This novel material, with its integrated structural and functional advantages, has been widely applied in my country's aerospace precision instruments and military electronic components, achieving significant application results.
[0003] Pressureless infiltration is an effective process for preparing high-volume-fraction ceramic particle-reinforced aluminum matrix composites. It not only boasts a short process flow, high production efficiency, uniform distribution of ceramic particles within the aluminum alloy matrix, and good ingot dimensional stability, but also facilitates large-scale fabrication. Applying high-volume-fraction silicon carbide-reinforced aluminum matrix composites prepared by pressureless infiltration to precision instrument components, and further improving their strength, elastic modulus, and thermal diffusivity, undoubtedly holds significant importance and engineering value. Summary of the Invention
[0004] The purpose of this invention is to provide a silicon carbide treatment method and a silicon carbide-reinforced aluminum matrix composite material. By chemically etching silicon carbide, the chemical and physical properties of the silicon carbide surface are altered, thereby improving the interfacial bonding between silicon carbide and the aluminum alloy matrix, and increasing the strength, elastic modulus, and thermal diffusivity of the silicon carbide-reinforced aluminum matrix composite material. To achieve the above objective,
[0005] This invention provides a silicon carbide processing method, comprising the following steps:
[0006] S1. The silicon carbide particles are subjected to a long-term immersion and heavy pickling treatment with high-concentration acid.
[0007] S2. Wash the pickled silicon carbide particles with water until neutral.
[0008] S3. Dry the washed silicon carbide particles to obtain activated silicon carbide particles.
[0009] Preferably, in S1, the high-concentration acid is hydrofluoric acid with a mass percentage concentration of 20% to 49%.
[0010] Preferably, in step S1, the duration of the long-term immersion and heavy pickling treatment is 24h to 96h.
[0011] Preferably, in S1, the median particle size D50 of the silicon carbide particles is 3μm to 120μm.
[0012] Preferably, in step S1, the purity of the silicon carbide particles is not less than 99.5%.
[0013] Preferably, in step S2, the silicon carbide particles are washed with deionized water.
[0014] Preferably, in step S3, the drying temperature is 120℃~150℃ and the drying time is 60min~180min.
[0015] A silicon carbide-reinforced aluminum matrix composite material includes an aluminum alloy matrix, wherein activated silicon carbide particles obtained above are composited within the aluminum alloy matrix.
[0016] Preferably, the volume fraction of the activated silicon carbide particles is 40% to 70%.
[0017] Preferably, the aluminum alloy is an aluminum-silicon-magnesium cast aluminum alloy.
[0018] The preparation method of the above-mentioned silicon carbide reinforced aluminum matrix composite material includes the following steps:
[0019] Activated silicon carbide particles are stacked in a graphite crucible to form a packing density of 40%–70%, and the top surface of the packing is flattened. The silicon carbide particles can be stacked using either pressing or vibration methods, ensuring a tight packing without any inter-particle connections. The frequency of the vibration compaction is set based on the pre-designed packing density, projected area, and height of the packing. Similarly, the pressing pressure is also set based on the packing density, projected area, and height of the packing.
[0020] Aluminum alloy ingots are placed on the upper surface of the packing. The amount of aluminum alloy ingots used is calculated based on the volume and porosity of the silicon carbide particle packing. The actual amount of aluminum alloy used is 10% to 20% more than the calculated theoretical amount.
[0021] A graphite crucible, a silicon carbide particle pack, and an aluminum alloy ingot are placed together in a heating furnace and heated and held at a temperature of 800℃~950℃ under a nitrogen atmosphere for 2h~15h. After cooling to room temperature, a silicon carbide-reinforced aluminum matrix composite material is obtained.
[0022] Silicon carbide particles are highly stable materials and generally do not react with acids. High-concentration hydrofluoric acid is highly corrosive and has a strong erosive effect on silicon-containing materials. When silicon carbide is immersed in high-concentration hydrofluoric acid for a prolonged period, the following changes occur on the silicon carbide surface: First, the fluoride ions in the hydrofluoric acid... Fluoride ions react to silicon atoms (Si) on the surface of silicon carbide, causing partial breakage of Si-C bonds. Secondly, fluoride ions combine with silicon or carbon atoms on the silicon carbide surface to form new fluorine-containing chemical bonds. The newly formed fluorine-containing chemical bonds and the partial breakage of Si-C bonds affect the chemical and physical properties of the silicon carbide particle surface, improve wettability and chemical reactivity with molten aluminum, thereby enhancing the interfacial bonding between the silicon carbide particles and the aluminum matrix, increasing load transfer efficiency, and reducing interfacial thermal resistance. Macroscopically, this manifests as an increase in the strength, elastic modulus, and thermal diffusivity of the aluminum-based composite material.
[0023] Existing technologies also employ low-concentration acidic solutions to treat silicon carbide. However, this treatment is primarily used to remove impurities introduced during powder processing or adhering to the surface of silicon carbide particles, or to remove the thin layer of amorphous silica on the silicon carbide surface, thereby improving the purity of the silicon carbide and obtaining high-purity silicon carbide particles. These operations do not affect the silicon carbide itself (including its surface). The silicon carbide used in this invention is high-purity silicon carbide particles that have undergone conventional processing. Surface activation of these high-purity silicon carbide particles is then performed to improve the bonding strength between the silicon carbide particles and the aluminum alloy, thereby enhancing the performance of silicon carbide-reinforced aluminum matrix composites.
[0024] The advantages and positive effects of the silicon carbide treatment method and silicon carbide reinforced aluminum matrix composite material described in this invention are as follows:
[0025] 1. This invention employs high-concentration hydrofluoric acid to subject silicon carbide particles to prolonged immersion and heavy pickling treatment, thereby altering the chemical and physical properties of the silicon carbide particle surface, promoting the bonding between the silicon carbide particles and the aluminum alloy matrix, improving the strength, elastic modulus, and thermal diffusivity of the aluminum-based composite material, enhancing the application efficiency of silicon carbide-reinforced aluminum-based composite materials in typical application scenarios such as aerospace precision instruments and electronic component packaging, and endowing components with higher structural precision stability and heat dissipation capabilities.
[0026] 2. The silicon carbide particle processing method described in this invention is simple to operate, low in cost, and produces uniform surface treatment of silicon carbide particles, making it easy to achieve industrial production.
[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Detailed Implementation
[0028] In the description of this invention, it should be noted that, unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.
[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0030] The technical solution of the present invention will be described in detail below through embodiments.
[0031] Example 1
[0032] S1. The silicon carbide particles were subjected to a long-term immersion and heavy pickling treatment using hydrofluoric acid with a mass percentage concentration of 20% for 96 hours. The median particle size (D50) of the silicon carbide particles was 90 μm.
[0033] S2. Wash the acid-washed silicon carbide particles with deionized water until neutral.
[0034] S3. Dry the washed silicon carbide particles at a temperature of 120°C for 180 minutes to obtain activated silicon carbide particles.
[0035] Activated silicon carbide particles were packed into a graphite crucible to form a bulk density of 55%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (45%) of the bulk by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 850°C, holding at that temperature for 8 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0036] Example 2
[0037] S1. The silicon carbide particles were subjected to a long-term immersion and heavy pickling treatment using hydrofluoric acid with a mass percentage concentration of 30% for 72 hours. The median particle size (D50) of the silicon carbide particles was 12.8 μm.
[0038] S2. Wash the acid-washed silicon carbide particles with deionized water until neutral.
[0039] S3. Dry the washed silicon carbide particles at a temperature of 130°C for 150 minutes to obtain activated silicon carbide particles.
[0040] Activated silicon carbide particles were packed into a graphite crucible to form a bulk density of 45%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (55%) of the bulk by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 880°C for 6 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0041] Example 3
[0042] S1. The silicon carbide particles were subjected to a long-term immersion and heavy pickling treatment using hydrofluoric acid with a mass percentage concentration of 35% for 60 hours. The median particle size (D50) of the silicon carbide particles was 120 μm.
[0043] S2. Wash the acid-washed silicon carbide particles with deionized water until neutral.
[0044] S3. Dry the washed silicon carbide particles at a temperature of 140℃ for 120 minutes to obtain activated silicon carbide particles.
[0045] Activated silicon carbide particles were packed into a graphite crucible to form a bulk density of 63%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (37%) by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 800°C, holding at that temperature for 15 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0046] Example 4
[0047] S1. The silicon carbide particles were subjected to a long-term, heavy acid pickling treatment using hydrofluoric acid with a mass percentage concentration of 40% for 36 hours. The median particle size (D50) of the silicon carbide particles was 3 μm.
[0048] S2. Wash the acid-washed silicon carbide particles with deionized water until neutral.
[0049] S3. Dry the washed silicon carbide particles at a temperature of 150°C for 90 minutes to obtain activated silicon carbide particles.
[0050] Activated silicon carbide particles were packed into a graphite crucible to form a bulk density of 40%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (60%) of the bulk by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 950°C for 2 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0051] Example 5
[0052] S1. The silicon carbide particles were subjected to a long-term immersion and heavy pickling treatment using hydrofluoric acid with a mass percentage concentration of 49% for 24 hours. The silicon carbide particles were composed of a mixture of particles with median particle sizes (D50) of 75µm and 17.3µm in an 8:2 ratio.
[0053] S2. Wash the acid-washed silicon carbide particles with deionized water until neutral.
[0054] S3. Dry the washed silicon carbide particles at a temperature of 150°C for 60 minutes to obtain activated silicon carbide particles.
[0055] Activated silicon carbide particles were packed into a graphite crucible to form a bulk density of 70%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (30%) of the bulk by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 920°C, holding at that temperature for 4 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0056] Comparative Example 1
[0057] The only difference between this comparative example and Example 1 is that the silicon carbide particles were not subjected to hydrofluoric acid immersion treatment but were used directly. The specific steps are as follows:
[0058] Silicon carbide particles were packed into a graphite crucible to form a bulk density of 55%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (45%) of the bulk by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 850°C, holding at that temperature for 8 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0059] The median particle size (D50) of the silicon carbide particles is 90 μm.
[0060] Comparative Example 2
[0061] The only difference between this comparative example and Example 2 is that the silicon carbide particles were used directly instead of being treated with hydrofluoric acid immersion. The specific steps are as follows:
[0062] Silicon carbide particles were packed into a graphite crucible to form a bulk density of 45%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (55%) of the bulk by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 880°C, holding at that temperature for 6 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0063] The median particle size (D50) of the silicon carbide particles is 12.8 μm.
[0064] Comparative Example 3
[0065] The only difference between this comparative example and Example 3 is that the silicon carbide particles were not subjected to hydrofluoric acid immersion treatment but were used directly. The specific steps are as follows:
[0066] Silicon carbide particles were packed into a graphite crucible to form a bulk density of 63%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (37%) of the bulk by 10%–20%. The graphite crucible and its contents were then placed in a nitrogen-filled heating device and heated to 800°C, holding at that temperature for 15 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0067] The median particle size (D50) of the silicon carbide particles is 120 μm.
[0068] Comparative Example 4
[0069] The only difference between this comparative example and Example 4 is that the silicon carbide particles were not subjected to hydrofluoric acid immersion treatment but were used directly. The specific steps are as follows:
[0070] Silicon carbide particles were packed into a graphite crucible to form a bulk density of 40%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (60%) of the bulk by 10%–20%. The graphite crucible and its contents were then placed in a nitrogen-filled heating device and heated to 950°C, held for 2 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0071] The median particle size (D50) of the silicon carbide particles is 3 μm.
[0072] Comparative Example 5
[0073] The only difference between this comparative example and Example 5 is that the silicon carbide particles were not subjected to hydrofluoric acid immersion treatment but were used directly. The specific steps are as follows:
[0074] Silicon carbide particles were packed into a graphite crucible to form a bulk density of 70%, and the upper surface of the bulk was flattened with a glass plate. An aluminum-silicon-magnesium (ASME) cast aluminum alloy ingot was placed on top, with the actual amount of aluminum alloy ingot exceeding the theoretical amount calculated based on the bulk volume and porosity (30%) of the bulk by 10%–20%. The graphite crucible and its contents were placed in a nitrogen-filled heating device and heated to 920°C, holding at that temperature for 4 hours. After cooling to room temperature, the contents were removed from the graphite crucible to obtain a silicon carbide-reinforced aluminum matrix composite ingot.
[0075] The silicon carbide particles are composed of a mixture of particles with median particle sizes (D50) of 75µm and 17.3µm in an 8:2 ratio.
[0076] The performance of silicon carbide reinforced aluminum matrix composite billets obtained in Examples 1-5 and Comparative Examples 1-5 was tested, and the results are shown in Tables 1, 2, 3, 4 and 5, respectively.
[0077] Table 1. Measured values of composite material performance indicators obtained in Example 1 and Comparative Example 1
[0078] ;
[0079] Table 2. Measured values of composite material performance indicators obtained in Example 2 and Comparative Example 2.
[0080] ;
[0081] Table 3. Measured values of composite material performance indicators obtained in Example 3 and Comparative Example 3.
[0082] ;
[0083] Table 4. Measured values of composite material performance indicators obtained in Example 4 and Comparative Example 4.
[0084] ;
[0085] Table 5. Measured values of composite material performance indicators obtained in Example 5 and Comparative Example 5.
[0086] ;
[0087] The performance test results of silicon carbide reinforced aluminum matrix composite billets obtained from Examples 1-5 and Comparative Examples 1-5 show that after silicon carbide particles are soaked in high-concentration hydrofluoric acid for a long time and heavily pickled, the bending strength, bending modulus of elasticity and thermal diffusivity of the obtained silicon carbide reinforced aluminum matrix composites are significantly improved.
[0088] Therefore, by employing the silicon carbide treatment method and silicon carbide reinforced aluminum matrix composite material described in this invention, the chemical corrosion treatment of silicon carbide alters the chemical and physical properties of the silicon carbide surface, thereby improving the interfacial bonding state between silicon carbide and the aluminum alloy matrix, and effectively enhancing the strength, elastic modulus, and thermal diffusivity of the silicon carbide reinforced aluminum matrix composite material.
[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A method for treating silicon carbide, characterized in that, Includes the following steps: S1. The silicon carbide particles are subjected to heavy acid pickling treatment by immersion in high-concentration acid. S2. Wash the pickled silicon carbide particles with water until neutral. S3. Dry the washed silicon carbide particles to obtain activated silicon carbide particles.
2. The silicon carbide processing method according to claim 1, characterized in that: In S1, the high-concentration acid is hydrofluoric acid with a mass percentage concentration of 20% to 49%.
3. The silicon carbide processing method according to claim 1, characterized in that: In S1, the soaking and heavy pickling treatment time is 24h~96h.
4. The silicon carbide processing method according to claim 1, characterized in that: In S1, the median particle size D50 of the silicon carbide particles is 3μm to 120μm.
5. The silicon carbide processing method according to claim 1, characterized in that: In S1, the purity of the silicon carbide particles is not less than 99.5%.
6. The silicon carbide processing method according to claim 1, characterized in that: In step S2, the silicon carbide particles are washed with deionized water.
7. The silicon carbide processing method according to claim 1, characterized in that: In step S3, the drying temperature is 120℃~150℃, and the drying time is 60min~180min.
8. A silicon carbide reinforced aluminum-based composite material, characterized in that: It includes an aluminum alloy matrix, wherein activated silicon carbide particles obtained by the silicon carbide treatment method according to any one of claims 1-7 are incorporated within the aluminum alloy matrix.
9. The silicon carbide reinforced aluminum matrix composite material according to claim 8, characterized in that: The volume fraction of the activated silicon carbide particles is 40% to 70%.
10. A silicon carbide reinforced aluminum matrix composite material according to claim 8, characterized in that: The aluminum alloy is an aluminum-silicon-magnesium cast aluminum alloy.