Graphene modified high-heat-conductivity aluminum-based composite material and powder metallurgy preparation method

Abstract

The invention provides a graphene modified high-heat-conductivity aluminum-based composite material and a powder metallurgy preparation method thereof. The material comprises reinforced grains and an aluminum substrate, wherein the composite boundary of the reinforced grains and the aluminum substrate contains high-heat-conductivity graphene nanosheets. The method comprises the following steps: (1) soaking the reinforced grains with a strong acid solution, subsequently washing with deionized water till being neutral, drying, and removing the surface impurities, thereby obtaining activated reinforced grains; (2) adding the activated reinforced grains into a graphene dispersion liquid, mechanically stirring or performing ultrasonic dispersion, and wrapping the graphene nanosheets on the surface, thereby preparing the graphene modified reinforced grains; and (3) mixing the graphene modified reinforced grains with the aluminum substrate powder, pressing into blanks, and sintering, thereby preparing the graphene modified high-heat-conductivity aluminum-based composite material. The composite material provided by the invention is good in chemical stability, high in thermal conductivity and can be used as a heat management material of a large-power semiconductor device.

Description

technical field [0001] The invention relates to the technical field of metal-based composite materials, in particular to a method for modifying the surface of reinforcement particles by using graphene, and then using powder metallurgy technology to prepare aluminum-based composite materials with high thermal conductivity. Background technique [0002] In recent years, in order to meet the development needs of electronic technology, the research of high thermal conductivity and low expansion metal matrix composites used as thermal management materials has made great progress. Particle-reinforced aluminum matrix composites have become an ideal choice for future electronic packaging materials due to the comprehensive advantages of aluminum matrix and reinforcement particles, light weight, high thermal conductivity, and low expansion. However, the currently selected reinforcement particles are mainly carbon or carbon-containing high thermal conductivity materials, such as silico...

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Problems solved by technology

However, document 3 "A predictive model for interfacial thermal conductance in surface metallized diamond aluminum matrix composites" (Materials and Design 55 (2014) 257-262) and document 4 "The effect of coating thickness on the thermal conductivity of titanium-coated diamond / aluminum composites" (Journal of Nonferrous Metals of China, 23 (2013) 802-808) has been confirmed from both theoretical and experimental aspects: the thermal conductivity of composite materials varies with the interface coating The thickness increases and drops sharply. Although the surface of diamond and other particles coated with W, Ti and other particles can improve the interface bonding and thermal conductivity of the composite material, it is still far from the theoretical value. The main problem is that : (1) Compared with particle reinforcement and aluminum matrix, the thermal conductivity of the interface layer is too low (such as W and Ti are 178W / mK and 21.9W / mK respectively); (2) The coating thickness is too large (generally higher than 100nm), the thermal resistance of the composite material interface increased due to the introduction of the coating is large, resulting in a large gap between the thermal conductivity of the composite material and the theoretical value; (3) the thickness and uniformity of the coating on the particle surface are difficult to control, and the interface modification effect is not good. ideal

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