Composite material, method of manufacturing the same, chassis, and semiconductor device
By constructing a silicon-carbon bilayer shell structure on the surface of silicon carbide particles and adding carbon nanosheets and amorphous powder, combined with a vacuum pressure infiltration process, the problems of interfacial wettability and thermal expansion coefficient mismatch in aluminum-silicon-silicon carbide composite materials were solved, and the preparation of composite materials with high thermal conductivity and controllable thermal expansion coefficient was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG SANZER PRECISION CERAMICS CO LTD
- Filing Date
- 2026-05-11
- Publication Date
- 2026-06-05
AI Technical Summary
Existing aluminum-silicon-silicon carbide composite materials suffer from bottlenecks in terms of interfacial wettability and thermal expansion coefficient mismatch, resulting in insufficient thermal conductivity and mechanical properties. Traditional modification methods are unable to simultaneously meet the requirements of low interfacial thermal resistance and high interfacial bonding strength.
A silicon-carbon bilayer shell structure was constructed on the surface of silicon carbide particles. Carbon nanosheets and hypereutectic aluminum-silicon amorphous powder were prepared as functional additives. Composite materials were prepared by vacuum pressure infiltration process to form a multilayer composite interface and regulate the matrix morphology and thermal expansion coefficient.
The thermal conductivity of the material was significantly improved, and the coefficient of thermal expansion of the material was controllably adjusted by regulating the dosage of each additive and process parameters, thereby optimizing the distribution of interfacial thermal stress and the mechanical properties of the matrix.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of composite material preparation technology, and relates to a composite material and its preparation method, chassis and semiconductor equipment. Background Technology
[0002] With the development of electronic information technology, key components of power devices face increasingly severe thermal management challenges. These components generate a large amount of heat during operation, and if this heat cannot be dissipated in a timely and effective manner, it will lead to decreased equipment performance, reduced reliability, or even failure. Aluminum-based composite materials, especially aluminum-silicon-silicon carbide composites, have shown great application potential in the field of thermal management due to their advantages such as low density, relatively low cost, and ease of processing. However, the performance of conventional Al-Si-SiC composite materials still faces two major bottlenecks.
[0003] First, the poor wettability and high interfacial thermal resistance between aluminum alloys and silicon carbide limit the improvement of the overall thermal conductivity of the material. Second, the mismatch in the coefficient of thermal expansion between the aluminum matrix and silicon carbide leads to significant internal stress during service, affecting its dimensional stability and cycle reliability. Furthermore, the coarse eutectic silicon phase in the matrix also deteriorates the mechanical properties of the material and scatters hot carriers. Existing technologies typically employ methods such as adding active elements (e.g., titanium, magnesium) or surface coating silicon carbide particles to improve interfacial wettability. However, these methods often introduce impurity elements or form a single interfacial transition layer, making it difficult to simultaneously meet the dual requirements of low interfacial thermal resistance and high interfacial bonding strength. For matrix modification, traditional methods mostly focus on alteration treatments, but their ability to control microstructure is limited, and it is difficult to construct an effective thermal expansion constraint network. Summary of the Invention
[0004] To address the shortcomings of existing technologies, the present invention aims to provide a composite material and its preparation method, chassis, and semiconductor equipment. By constructing a silicon-carbon double-shell structure on the surface of silicon carbide particles, preparing carbon nanosheets and hypereutectic aluminum-silicon amorphous powder as functional additives, mixing the above materials with matrix powder to form a preform, and then performing composite by vacuum pressure impregnation process, thereby meeting the needs of actual production.
[0005] To achieve this objective, the present invention adopts the following technical solution:
[0006] In a first aspect, the present invention provides a method for preparing a composite material, the method comprising:
[0007] S1, SiC particles are placed in a reactor, silicon-containing gas is introduced for silicon deposition, and then carbon-containing gas is introduced for carbon deposition to obtain composite powder;
[0008] S2, carbon nanosheet powder is prepared by dispersing graphite powder in deionized water;
[0009] S3, smelting aluminum alloy and preparing amorphous powder;
[0010] S4. The composite powder, carbon nanosheet powder, amorphous powder and alloy powder are mixed and then pressed into a mold to obtain a preform. The preform is placed on top of the alloy ingot and placed in a crucible for heat preservation. Inert gas is introduced to pressurize and maintain the temperature to obtain a composite material.
[0011] Specifically, it includes:
[0012] S1, SiC particles are placed in a fluidized bed chemical vapor deposition reactor, the temperature is adjusted to the first temperature, and SiH4 / Ar mixed gas is introduced for silicon deposition. The SiH4 gas source is stopped, the temperature is adjusted to the second temperature, and C2H2 / Ar mixed gas is introduced for carbon deposition. After deposition, only argon gas is introduced, and the composite powder is obtained by furnace cooling.
[0013] S2, dispersing graphite powder in deionized water, sonicating and centrifuging, collecting carbon nanosheets in the supernatant, washing and drying to obtain carbon nanosheet powder.
[0014] S3, Al-25wt.%Si alloy is melted in a vacuum induction furnace. After melting, amorphous ribbon is prepared by single-roll rapid cooling. The amorphous ribbon is then placed in a ball mill jar pre-cooled by liquid nitrogen and ball-milled to obtain amorphous powder.
[0015] S4. The composite powder, carbon nanosheet powder, amorphous powder and Al-25wt.%Si alloy powder are mixed and pressed into a mold to obtain a preform. The preform and Al-25wt.%Si alloy ingot are placed in a crucible with the preform above the Al-25wt.%Si alloy ingot. The temperature is adjusted to the third temperature under vacuum and held. After the ingot is completely melted, Ar gas is introduced to pressurize and maintain the temperature. The pressure is maintained and cooled to the fourth temperature. Then the furnace is cooled to room temperature. The surface metal is removed to obtain a composite material.
[0016] In this invention, combining the preparation schemes and performance test results of Examples 1-4, at the interface level, when the liquid Al-Si alloy is infiltrated into the preform, the melt first contacts the outermost amorphous carbon layer of the SiC@Si@C particles. Due to the chemical potential difference between Al and C, an interfacial reaction occurs, generating a layer of nanocrystalline Al4C3 in situ. This Al4C3 phase has a low interfacial energy with the Al-Si melt, improving wettability and forming chemical bonds with the matrix. This reaction has a certain self-limiting characteristic, that is, the generated Al4C3 layer can act as a solid-state diffusion barrier layer, kinetically partially hindering the direct and rapid reaction between liquid Al and the inner silicon layer. Subsequently, a concentration gradient exists between the inner nanocrystalline silicon covered by the Al4C3 layer and the surrounding liquid Al-Si matrix, driving solid-liquid atomic interdiffusion. Silicon atoms dissolve from the solid layer into the liquid phase, forming a gradient alloy region with continuously varying silicon concentration between the Al4C3 layer and the substrate. This gradient region eliminates the original abrupt interface to a certain extent, thereby mitigating the stress concentration caused by the mismatch in thermal expansion coefficients between SiC and the Al substrate during thermal cycling.
[0017] At the matrix level, the added carbon nanosheets can serve as heterogeneous nucleation substrates for the eutectic silicon phase in the liquid phase. Their surfaces provide low-energy attachment sites for silicon atoms, lowering the activation energy barrier for nucleation, thereby increasing the nucleation density of the eutectic silicon and constraining its growth morphology, leading to a refinement of the silicon phase in the final solidified structure. Secondly, the Al-Si amorphous powder added to the matrix, as a thermodynamically metastable phase, typically crystallizes during the heat preservation stage of the infiltration process. This process is an exothermic phase transition, and the released latent heat can cause a temperature rise in the micrometer-scale region. This local environment makes the larger eutectic silicon phase already present in the surrounding matrix thermodynamically unstable and causes it to dissolve. As the heat and composition of this micro-region reach equilibrium with the surrounding matrix through diffusion, the dissolved silicon will reprecipitate in a finer morphology on available nucleation sites such as carbon nanosheets.
[0018] Ultimately, in terms of heat transport, the formed gradient chemically bonded interfaces reduce thermal boundary resistance, providing a continuous pathway for heat flow; the refinement and dispersion of the silicon phase in the matrix reduces the thermal resistance of the matrix. Regarding thermal expansion, the high-strength interfaces ensure the effective transfer of mechanical stress from the matrix to the low thermal expansion coefficient of the SiC network; simultaneously, the microstructure-controlled matrix possesses a higher elastic modulus, enhancing its resistance to thermal deformation. Therefore, by controlling the initial state and content of each additive, the degree of interfacial reaction and the level of matrix phase transformation can be regulated, thereby achieving adjustment of the material's final thermal expansion coefficient.
[0019] In summary, this invention constructs a silicon-carbon bilayer shell structure on the surface of silicon carbide particles, prepares carbon nanosheets and hypereutectic aluminum-silicon amorphous powder as functional additives, and combines them with a vacuum pressure infiltration process. This reduces thermal boundary resistance at the interface level, improves the chemical bonding between the Al matrix and SiC particles, refines and disperses the eutectic silicon phase at the matrix level, and optimizes the thermal stress distribution. As a result, the aluminum-silicon-silicon carbide composite material significantly improves the overall thermal conductivity. Furthermore, by adjusting the content of each functional component and the infiltration process conditions, the degree of interfacial reaction and matrix structure evolution can be controlled, thereby achieving controllable adjustment of the material's coefficient of thermal expansion.
[0020] In a preferred embodiment of the present invention, in S1, the particle size distribution of the SiC particles is 50 μm and 15 μm, with a mass ratio of 3:1.
[0021] In some alternative embodiments, the first temperature is 550-600°C, for example, it can be 550°C, 555°C, 560°C, 565°C, 570°C, 575°C, 580°C, 585°C, 590°C, 595°C or 600°C, but is not limited to the listed values, other unlisted values within this range are also applicable.
[0022] In some optional embodiments, the total flow rate of the SiH4 / Ar mixture is 2000 sccm, the flow rate of SiH4 is 40 sccm, and the flow rate of Ar is 1960 sccm.
[0023] In some alternative embodiments, the silicon deposition time is 15-30 min, for example, it can be 15 min, 16.5 min, 18 min, 19.5 min, 21 min, 22.5 min, 24 min, 25.5 min, 27 min, 28.5 min or 30 min, but is not limited to the listed values, other unlisted values within this range are also applicable.
[0024] In some alternative embodiments, the second temperature is 650-700°C, for example, it can be 650°C, 655°C, 660°C, 665°C, 670°C, 675°C, 680°C, 685°C, 690°C, 695°C or 700°C, but is not limited to the listed values, other unlisted values within this range are also applicable.
[0025] In some optional embodiments, the total flow rate of the C2H2 / Ar mixture is 2000 sccm, the flow rate of C2H2 is 40 sccm, and the flow rate of Ar is 1960 sccm.
[0026] In some alternative embodiments, the carbon deposition time is 15-30 min, for example, it can be 15 min, 16.5 min, 18 min, 19.5 min, 21 min, 22.5 min, 24 min, 25.5 min, 27 min, 28.5 min or 30 min, but is not limited to the listed values, other unlisted values within this range are also applicable.
[0027] As a preferred technical solution of the present invention, in S2, the mass ratio of graphite powder to deionized water is (0.2-0.3):(15-20), for example, it can be (0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, 0.27, 0.28, 0.29 or 0.3):(15, 15.5, 16, 16.5, 17, 17.5, 18, 18.5, 19, 19.5 or 20), but it is not limited to the listed values, and other unlisted values within this range are also applicable.
[0028] In some alternative embodiments, the ultrasound duration is 40-50 minutes, for example, 40 minutes, 41 minutes, 42 minutes, 43 minutes, 44 minutes, 45 minutes, 46 minutes, 47 minutes, 48 minutes, 49 minutes, or 50 minutes, but is not limited to the listed values; other unlisted values within this range are also applicable.
[0029] As a preferred embodiment of the present invention, in S3, the injection pressure of the single-roller rapid cooling method is 5×10⁻⁶. 4 -6×10 4 Pa, the normal to the nozzle and the roller surface is approximately 14°, for example: the injection pressure is (5×10 Pa). 4 5.1×10 4 5.2×10 4 5.3×10 4 5.4×10 4 5.5×10 4 5.6×10 4 5.7×10 4 5.8×10 4 5.9×10 4 Or 6×10 4 The nozzle is at approximately 14° to the normal of the roller surface, but this is not limited to the listed values; other unlisted values within this range also apply.
[0030] In some optional embodiments, the linear velocity of the roller surface in the single-roller rapid cooling method is 10-12 m / s, and the spraying distance is 0.5-1 mm. For example, the linear velocity of the roller surface can be (10, 10.2, 10.4, 10.6, 10.8, 11.0, 11.2, 11.4, 11.6, 11.8 or 12) m / s, and the spraying distance can be (0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95 or 1) mm, but it is not limited to the listed values. Other unlisted values within this range are also applicable.
[0031] As a preferred embodiment of the present invention, in S4, the mass ratio of the composite powder, carbon nanosheet powder, amorphous powder, Al-25wt.%Si alloy powder to Al-25wt.%Si alloy ingot is (58-62):(0.2-0.3):(0.15-0.25):(38-42):(36-39), for example, it can be (58, 58.4, 58.8, 59.2, 59.6, 60.0, 60.4, 60.8, 61.2, 61.6 or 62):(0.2, 0.21, 0.22, 0.23, 0.24, 0.25, 0.26, ... 0.27, 0.28, 0.29 or 0.3: (0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.21, 0.22, 0.23, 0.24 or 0.25): (38, 38.4, 38.8, 39.2, 39.6, 40.0, 40.4, 40.8, 41.2, 41.6 or 42): (36, 36.3, 36.6, 36.9, 37.2, 37.5, 37.8, 38.1, 38.4, 38.7 or 39), but not limited to the listed values; other unlisted values within this range also apply.
[0032] In some alternative embodiments, the third temperature is 800-850°C, for example, it can be 800°C, 805°C, 810°C, 815°C, 820°C, 825°C, 830°C, 835°C, 840°C, 845°C or 850°C, but is not limited to the listed values, other unlisted values within this range are also applicable.
[0033] In some optional embodiments, the time for holding the third temperature is 25-35 minutes, for example, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, 30 minutes, 31 minutes, 32 minutes, 33 minutes, 34 minutes or 35 minutes, but is not limited to the listed values, and other unlisted values within this range are also applicable.
[0034] In some optional embodiments, the pressure of the introduced Ar gas is 7-9 MPa, for example, it can be 7.0 MPa, 7.2 MPa, 7.4 MPa, 7.6 MPa, 7.8 MPa, 8.0 MPa, 8.2 MPa, 8.4 MPa, 8.6 MPa, 8.8 MPa or 9.0 MPa, but is not limited to the listed values, other unlisted values within this range are also applicable.
[0035] In some optional embodiments, the time for which Ar gas is introduced and pressurized and maintained is 55-65 minutes, for example, 55 minutes, 56 minutes, 57 minutes, 58 minutes, 59 minutes, 60 minutes, 61 minutes, 62 minutes, 63 minutes, 64 minutes or 65 minutes, but is not limited to the listed values, and other unlisted values within this range are also applicable.
[0036] In some alternative embodiments, the fourth temperature is 500-520°C, for example, it can be 500°C, 502°C, 504°C, 506°C, 508°C, 510°C, 512°C, 514°C, 516°C, 518°C or 520°C, but is not limited to the listed values, other unlisted values within this range are also applicable.
[0037] In a second aspect, the present invention provides a composite material prepared by the preparation method described in the first aspect.
[0038] Thirdly, the present invention provides a chassis made of the composite material described in the second aspect.
[0039] Fourthly, the present invention provides a semiconductor device comprising the chassis described in the third aspect.
[0040] Compared with the prior art, the beneficial effects of the present invention are as follows: by constructing a double-shell structure on the surface of SiC particles, a multi-layer composite interface is generated in situ, which alleviates interfacial thermal stress and reduces interfacial thermal resistance; Al-Si amorphous powder is introduced as a functional additive, and its exothermic crystallization at a specific temperature is utilized to reshape the coarse needle / plate eutectic silicon in the matrix into fine, dispersed particles through a dissolution-reprecipitation process, thereby improving the thermal conductivity of the matrix itself; carbon nanosheets, as efficient heterogeneous nucleation sites, work together with Al-Si amorphous powder to construct a thermal expansion constraint network. By controlling the dosage of each additive and process parameters, the microstructure and strengthening degree of the matrix can be effectively adjusted, thereby achieving precise control of the macroscopic thermal expansion coefficient of the composite material. Detailed Implementation
[0041] The technical solution of the present invention will be described in detail below with reference to specific embodiments. The embodiments described herein are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are explanatory and exemplary and should not be construed as limiting the implementation of the present invention or the scope of protection of the present invention. In addition to the embodiments described herein, those skilled in the art can also adopt other obvious technical solutions based on the content disclosed in the claims and the specification of this application. These technical solutions include those that make any obvious substitutions and modifications to the embodiments described herein.
[0042] The chemical reagents used in the embodiments and comparative examples of this invention are all commercially available products and have not undergone any further purification treatment.
[0043] Example 1
[0044] This embodiment provides a composite material and its preparation method, the preparation method specifically including the following steps:
[0045] S1, SiC particles are placed in a fluidized bed chemical vapor deposition reactor. The particle size distribution of the SiC particles is 50μm and 15μm, with a mass ratio of 3:1. The temperature is adjusted to 550℃, and a SiH4 / Ar mixed gas is introduced for silicon deposition for 25 min. The total flow rate of the SiH4 / Ar mixed gas is 2000 sccm, the flow rate of SiH4 is 40 sccm, and the flow rate of Ar is 1960 sccm. The SiH4 gas supply is stopped, the temperature is adjusted to 680℃, and a C2H2 / Ar mixed gas is introduced for carbon deposition for 30 min. The total flow rate of the C2H2 / Ar mixed gas is 2000 sccm, the flow rate of C2H2 is 40 sccm, and the flow rate of Ar is 1960 sccm. After deposition, only argon gas is introduced, and the composite powder is obtained by furnace cooling.
[0046] S2, 0.2g of graphite powder was dispersed in 18g of deionized water, sonicated for 50min and centrifuged, and the carbon nanosheets in the supernatant were collected, washed and dried to obtain carbon nanosheet powder;
[0047] S3, an Al-25wt.%Si alloy was melted in a vacuum induction furnace, and then an amorphous ribbon was prepared using a single-roll quenching method. The spray pressure of the single-roll quenching method was 5.5 × 10⁻⁶. 4 Pa, the normal of the nozzle to the roller surface is about 14°, the roller surface linear velocity is 12m / s, the spraying distance is 0.8mm, and then the amorphous ribbon is placed in a ball milling jar pre-cooled by liquid nitrogen for ball milling to obtain amorphous powder;
[0048] S4. Mix 58g of composite powder, 0.25g of carbon nanosheet powder, 0.25g of amorphous powder, and 40g of Al-25wt.%Si alloy powder, and press them into a mold to obtain a preform. Place the preform on top of 39g of Al-25wt.%Si alloy ingot in a crucible, adjust the temperature to 800℃ under vacuum and hold for 30min. After the ingot is completely melted, introduce Ar gas and pressurize to 8MPa and hold for 55min. Continue to maintain the pressure and cool to 515℃, then cool to room temperature with the furnace. Remove the surface metal to obtain a composite material.
[0049] Example 2
[0050] This embodiment provides a composite material and its preparation method, the preparation method specifically including the following steps:
[0051] S1. SiC particles with a particle size distribution of 50μm and 15μm and a mass ratio of 3:1 are placed in a fluidized bed chemical vapor deposition reactor. The temperature is adjusted to 600℃, and a SiH4 / Ar mixed gas is introduced for silicon deposition for 20 min. The total flow rate of the SiH4 / Ar mixed gas is 2000 sccm, the flow rate of SiH4 is 40 sccm, and the flow rate of Ar is 1960 sccm. The SiH4 gas supply is stopped, the temperature is adjusted to 650℃, and a C2H2 / Ar mixed gas is introduced for carbon deposition for 25 min. The total flow rate of the C2H2 / Ar mixed gas is 2000 sccm, the flow rate of C2H2 is 40 sccm, and the flow rate of Ar is 1960 sccm. After deposition, only argon gas is introduced, and the composite powder is obtained by furnace cooling.
[0052] S2, 0.3g of graphite powder was dispersed in 15g of deionized water, sonicated for 45min and centrifuged, and the carbon nanosheets in the supernatant were collected, washed and dried to obtain carbon nanosheet powder.
[0053] S3, an Al-25wt.%Si alloy was melted in a vacuum induction furnace, and then an amorphous ribbon was prepared using a single-roll quenching method. The spray pressure of the single-roll quenching method was 5×10⁻⁶. 4 Pa, the normal of the nozzle to the roller surface is about 14°, the roller surface linear velocity is 11m / s, the spraying distance is 1mm, and then the amorphous ribbon is placed in a ball milling jar pre-cooled by liquid nitrogen for ball milling to obtain amorphous powder;
[0054] S4. 60g of composite powder, 0.22g of carbon nanosheet powder, 0.15g of amorphous powder, and 42g of Al-25wt.%Si alloy powder were mixed and pressed into a mold to obtain a preform. The preform was placed on top of 37g of Al-25wt.%Si alloy ingot in a crucible. The temperature was adjusted to 850℃ under vacuum and held for 25min. After the ingot was completely melted, Ar gas was introduced and pressurized to 7.5MPa and held for 65min. The pressure was then maintained and cooled to 500℃. The furnace was then cooled to room temperature. The surface metal was removed to obtain a composite material.
[0055] Example 3
[0056] This embodiment provides a composite material and its preparation method, the preparation method specifically including the following steps:
[0057] S1, SiC particles are placed in a fluidized bed chemical vapor deposition reactor. The particle size distribution of the SiC particles is 50μm and 15μm, with a mass ratio of 3:1. The temperature is adjusted to 580℃, and a SiH4 / Ar mixed gas is introduced for silicon deposition for 15 min. The total flow rate of the SiH4 / Ar mixed gas is 2000 sccm, the flow rate of SiH4 is 40 sccm, and the flow rate of Ar is 1960 sccm. The SiH4 gas supply is stopped, the temperature is adjusted to 690℃, and a C2H2 / Ar mixed gas is introduced for carbon deposition for 18 min. The total flow rate of the C2H2 / Ar mixed gas is 2000 sccm, the flow rate of C2H2 is 40 sccm, and the flow rate of Ar is 1960 sccm. After deposition, only argon gas is introduced, and the composite powder is obtained by furnace cooling.
[0058] S2, 0.28g of graphite powder was dispersed in 20g of deionized water, sonicated for 40min and centrifuged, and the carbon nanosheets in the supernatant were collected, washed and dried to obtain carbon nanosheet powder;
[0059] S3, an Al-25wt.%Si alloy was melted in a vacuum induction furnace, and then an amorphous ribbon was prepared using a single-roll quenching method. The spray pressure of the single-roll quenching method was 5.8 × 10⁻⁶. 4 Pa, the normal of the nozzle to the roller surface is about 14°, the linear velocity of the roller surface is 10m / s, the spraying distance is 0.6mm, and then the amorphous ribbon is placed in a ball milling jar pre-cooled by liquid nitrogen for ball milling to obtain amorphous powder;
[0060] S4. 62g of composite powder, 0.2g of carbon nanosheet powder, 0.2g of amorphous powder, and 39g of Al-25wt.%Si alloy powder were mixed and pressed into a mold to obtain a preform. The preform was placed on top of 36g of Al-25wt.%Si alloy ingot and placed in a crucible. The temperature was adjusted to 810℃ under vacuum and held for 28min. After the ingot was completely melted, Ar gas was introduced and pressurized to 9MPa and held for 60min. The pressure was then maintained and cooled to 520℃. The furnace was then cooled to room temperature, and the surface metal was removed to obtain a composite material.
[0061] Example 4
[0062] This embodiment provides a composite material and its preparation method, the preparation method specifically including the following steps:
[0063] S1, SiC particles are placed in a fluidized bed chemical vapor deposition reactor. The particle size distribution of the SiC particles is 50μm and 15μm, with a mass ratio of 3:1. The temperature is adjusted to 570℃, and a SiH4 / Ar mixed gas is introduced for silicon deposition for 28 min. The total flow rate of the SiH4 / Ar mixed gas is 2000 sccm, the flow rate of SiH4 is 40 sccm, and the flow rate of Ar is 1960 sccm. The SiH4 gas supply is stopped, the temperature is adjusted to 700℃, and a C2H2 / Ar mixed gas is introduced for carbon deposition for 15 min. The total flow rate of the C2H2 / Ar mixed gas is 2000 sccm, the flow rate of C2H2 is 40 sccm, and the flow rate of Ar is 1960 sccm. After deposition, only argon gas is introduced, and the composite powder is obtained by furnace cooling.
[0064] S2, 0.26g of graphite powder was dispersed in 16g of deionized water, sonicated for 42min and centrifuged, and the carbon nanosheets in the supernatant were collected, washed and dried to obtain carbon nanosheet powder.
[0065] S3, an Al-25wt.%Si alloy was melted in a vacuum induction furnace, and then an amorphous ribbon was prepared using a single-roll quenching method. The spray pressure of the single-roll quenching method was 6×10⁻⁶. 4 Pa, the normal of the nozzle to the roller surface is about 14°, the roller surface linear velocity is 11.5m / s, the spraying distance is 0.5mm, and then the amorphous ribbon is placed in a ball milling jar pre-cooled by liquid nitrogen for ball milling to obtain amorphous powder;
[0066] S4. 59g of composite powder, 0.3g of carbon nanosheet powder, 0.18g of amorphous powder, and 38g of Al-25wt.%Si alloy powder were mixed and pressed into a mold to obtain a preform. The preform was placed on top of 38g of Al-25wt.%Si alloy ingot and placed in a crucible. The temperature was adjusted to 830℃ under vacuum and held for 35min. After the ingot was completely melted, Ar gas was introduced and pressurized to 7MPa and held for 58min. The pressure was then maintained and cooled to 505℃. The furnace was then cooled to room temperature, and the surface metal was removed to obtain a composite material.
[0067] Comparative Example 1
[0068] This comparative example provides a composite material and its preparation method. The difference between this example and Example 1 is that, in S4, undeposited SiC particles of equal mass are used to replace the composite powder, while other process parameters and operating conditions are exactly the same as in Example 1.
[0069] Comparative Example 2
[0070] This comparative example provides a composite material and its preparation method. The difference between this example and Example 1 is that no carbon nanosheet powder is added in S4, while the other process parameters and operating conditions are exactly the same as in Example 1.
[0071] Comparative Example 3
[0072] This comparative example provides a composite material and its preparation method. The difference between this example and Example 1 is that no amorphous powder is added in S4, while the other process parameters and operating conditions are exactly the same as in Example 1.
[0073] The performance of the composite materials prepared in Examples 1-4 and Comparative Examples 1-3 was tested:
[0074] The thermal conductivity test method is ASTM E1461;
[0075] The test method for the coefficient of thermal expansion is ASTM E228.
[0076] The test results are shown in Table 1.
[0077] Table 1. Performance test results of composite materials prepared in Examples 1-4 and Comparative Examples 1-3
[0078]
[0079] As can be seen from the performance test results of Examples 1-4 and Comparative Examples 1-3 in Table 1, under the conditions of using composite powder, carbon nanosheet powder, and amorphous powder and preparing according to steps S1-S4, the thermal conductivity of the obtained aluminum-silicon-silicon carbide composite material is significantly higher than that of the comparative examples that did not use the above-mentioned common structure or lacked any of the functional additives. This indicates that the combination of silicon-carbon double-shell particles, carbon nanosheets, and hypereutectic aluminum-silicon amorphous powder, along with the vacuum pressure infiltration process, is the key to achieving high thermal conductivity in this invention. Meanwhile, by changing the ratio of composite powder, carbon nanosheet powder, amorphous powder, and Al-25wt.%Si alloy powder in Examples 1-4, and by adjusting the heat preservation and cooling conditions during the infiltration process, the coefficient of thermal expansion of the material can be controlled within a certain range. This demonstrates that, within the common process framework of this invention, the coefficient of thermal expansion can be adjusted while maintaining high thermal conductivity.
[0080] As shown in Table 1, compared to Example 1, the thermal conductivity of Comparative Example 1 decreased while the coefficient of thermal expansion increased; the thermal conductivity of Comparative Example 2 decreased while the coefficient of thermal expansion increased; and the thermal conductivity of Comparative Example 3 decreased while the coefficient of thermal expansion increased. This is because Comparative Example 1 used undeposited SiC particles, resulting in poor initial wettability between SiC and the molten Al-Si alloy. During impregnation, unwetted areas, interfacial voids, or discontinuous contact were more likely to occur, increasing interfacial thermal resistance. Simultaneously, poor interfacial contact prevented the effective transfer of mechanical stress from the matrix to the SiC network, thus increasing the coefficient of thermal expansion. Comparative Example 2 did not add carbon nanosheet powder. Carbon nanosheets, acting as heterogeneous nucleation sites, can increase the nucleation density of eutectic Si and inhibit growth. The absence of carbon nanosheets may coarsen the Si particle size, decrease the thermal conductivity, and slightly decrease the local elastic modulus, leading to an increase in the coefficient of thermal expansion. Comparative Example 3 did not add amorphous powder, weakening the original wetting / interface optimization effect and preventing dissolution and re-precipitation to refine the eutectic Si, thus decreasing the thermal conductivity and increasing the coefficient of thermal expansion.
[0081] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.
Claims
1. A method for preparing a composite material, characterized in that, The preparation method includes: S1, SiC particles are placed in a reactor, silicon-containing gas is introduced for silicon deposition, and then carbon-containing gas is introduced for carbon deposition to obtain composite powder; S2, carbon nanosheet powder is prepared by dispersing graphite powder in deionized water; S3, smelting aluminum alloy and preparing amorphous powder; S4. The composite powder, carbon nanosheet powder, amorphous powder and alloy powder are mixed and then pressed into a mold to obtain a preform. The preform is placed on top of the alloy ingot and placed in a crucible for heat preservation. Inert gas is introduced to pressurize and maintain the temperature to obtain a composite material.
2. The method for preparing a composite material according to claim 1, characterized in that, In S1: The SiC particles have a particle size distribution of 50 μm and 15 μm, with a mass ratio of 3:
1.
3. The method for preparing a composite material according to claim 2, characterized in that, In S1: The silicon-containing gas is a SiH4 / Ar mixture with a total flow rate of 2000 sccm, a SiH4 flow rate of 40 sccm, and an Ar flow rate of 1960 sccm.
4. The method for preparing a composite material according to claim 3, characterized in that, In S1: The carbon-containing gas is a C2H2 / Ar mixture with a total flow rate of 2000 sccm, a C2H2 flow rate of 40 sccm, and an Ar flow rate of 1960 sccm.
5. The method for preparing a composite material according to claim 1, characterized in that, In S2: The mass ratio of graphite powder to deionized water is (0.2-0.3):(15-20).
6. The method for preparing a composite material according to claim 1, characterized in that, In S3: Amorphous powder was prepared using a single-roller quenching method, with a spray pressure of 5 × 10⁻⁶. 4 -6×10 4 Pa, the normal to the nozzle and the roller surface is approximately 14°.
7. The method for preparing a composite material according to claim 6, characterized in that, In S3: The linear velocity of the roller surface in the single-roller rapid cooling method is 10-12 m / s, and the spraying distance is 0.5-1 mm.
8. The method for preparing a composite material according to claim 1, characterized in that, In S4: The mass ratio of the composite powder, carbon nanosheet powder, amorphous powder, alloy powder and alloy ingot is (58-62):(0.2-0.3):(0.15-0.25):(38-42):(36-39).
9. The method for preparing a composite material according to claim 8, characterized in that, In S4: The inert gas is Ar gas, and the pressure of the Ar gas introduced and pressurized is 7-9 MPa.
10. A composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-9.
11. A chassis, characterized in that, The chassis is made of the composite material described in claim 10.
12. A semiconductor device, characterized in that, Includes the chassis for semiconductor devices as described in claim 11.