Aluminum-silicon alloy graphite composite heat conduction material and preparation method and application thereof

Abstract

The invention provides an aluminum-silicon alloy graphite composite heat conduction material, and a preparation method and an application thereof, the aluminum-silicon alloy graphite composite heat conduction material is prepared by mixing aluminum-silicon alloy powder with graphite packing and then performing hot pressed sintering for the obtained mixture under a vacuum condition; and in the material, the graphite packing is evenly dispersed in an aluminum-silicon alloy matrix. The material provided by the invention has relatively higher heat conductivity, relatively higher compactness, relatively higher effective strength and a relatively lower coefficient of thermal expansion, and can be used for manufacturing high-power electronic devices so as to solve a difficult problem of heat conduction of the high-power electronic devices.

Description

Technical field [0001] The invention relates to an aluminum-silicon alloy graphite composite heat-conducting material and its preparation and application, belonging to the technical field of thermal management materials. Background technique [0002] As electronic devices continue to develop in the direction of miniaturization, light weight and high performance, their power density continues to increase, and the heat per unit volume is increasing. An increase in temperature will increase the thermal stress between the packaging material and the chip, and overheating will seriously affect the performance, reliability and service life of electronic products. Therefore, the heat conduction problem of high-power electronic devices has become an urgent issue to be solved. [0003] Traditional heat conduction methods such as convection heat exchange and forced air cooling have been difficult to meet the heat conduction requirements of high-power electronic devices. The best method is to...

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Problems solved by technology

The common process of the existing process preparation technology is powder metallurgy preparation, but in the preparation process, there are mainly the following three difficulties: (1) the aluminum-based graphite composite material is prepared by pressing first and then sintering, because the surface of the aluminum metal powder It is easy to oxidize, resulting in low sintering density and damage to the strength of the composite material; (2) the melting point of pure aluminum is high (660°C), and the preparation of aluminum-based composite materials needs to be sintered at a high temperature above 500°C for a long time to form a dense structure, which is easy Lead to the formation of harmful interfacial reaction phase Al at the interface of aluminum and graphite 4 C 3 , leading to a sharp decrease in the strength of the composite material, and it is easy to break; (3) Due to the large difference in thermal expansion coefficient between aluminum and graphite, it is easy to produce local deformation at the interface during the sintering process, resulting in cracking of the aluminum and graphite interface, which damages the thermal conductivity of the composite material rate and intensity

There are also researchers trying to use the impregnation method, which includes pressure infiltration and air pressure infiltration to prepare aluminum-graphite sheet composites. Researchers have found that graphite sheets overlap each other under pressure, and it is difficult for Al atoms to diffuse or impregnate graphite sheets. Between them, there is great difficulty in the composite forming of the aluminum matrix and the graphite sheet, which in turn affects the thermal conductivity of the material

Some researchers also used spark plasma sintering to prepare aluminum-graphite sheet composites, but found that the graphite sheets in the composite structure were easily bent under pressure.

[0008] Although aluminum-graphite composites have great potential, the thermal conductivity of aluminum-graphite composites reported in existing studies is not very satisfactory, and the development of aluminum-based graphite composites is not smooth, mainly because of the impact on aluminum-graphite composites. There are many factors affecting the thermal conductivity of graphite composites, such as the type, shape, size, volume fraction, orientation, and interface structure of graphite fillers.

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