Preparation of nickel nanoparticle-decorated graphene/copper composites with enhanced interfacial bonding and heat dissipation properties

Abstract

Because of its high thermal conductivity, graphene has been considered as an ideal reinforcement material in the fabrication of metal-based heat dissipation composite materials for electronic packaging applications. However, due to the poor interfacial bonding between graphene and metals such as copper and silver, the excellent performance of graphene has not been fully utilized, which greatly limits the development and application of metal/graphene composites. In this study, we propose a modification process of graphene, in which nickel nanoparticles with an average size of 72.8 nm are grown on oxygen plasma treated graphene (OPTG) by thermal reduction to yield a number density of 70 nanoparticles/μm2. The OPTG sheets decorated with nickel nanoparticles (Ni-OPTG) are added to copper nanoparticles as reinforcing layers to form Ni-OPTG/copper (Ni-OPTG/Cu) composites. Because the nickel nanoparticles can form C-O-Ni bonds with OPTG, and be easily sintered with copper, the interfacial bonding of the graphene/copper composite is enhanced, and the heat conductivity and shear strength of the sintered composite can be significantly improved. With the addition of only 0.1 wt% Ni-OPTG, the sintered copper/graphene composite achieve a thermal conductivity of 216.2 W/m·K and a shear strength of 56.3 MPa, which are 105.3 % and 87.3 % larger than the corresponding values of sintered copper nanoparticles, respectively. With these advantages, the Ni-OPTG/Cu composites have an excellent potential for use in packaging applications for high-power electronic chips and devices.