Wear Rate and Thermal Conductivity of a Copper-Plated Graphite Flake/Aluminum Composite

Aluminum matrix composites with nondirectional graphite-flake reinforcement were fabricated by hot-press sintering. To avoid interfacial reactions in the graphite-flake-reinforced composites, copper (Cu), with a thickness of approximately 50 μm, was coated on the graphite flakes by chemical plating. The results show that the Cu is uniformly distributed on the surface of graphite flakes. The thickness of the Cu plating is in the range of 15.3–21.2 μm. For volume fractions of the nondirectional graphite flakes ranging from 40% to 70%, the Al/Cu-plated graphite-flake (Cu-GF) composites display thermal conductivities from 328 W/m K to 612 W/m K. The theoretical values calculated by the parallel alternate layer model are slightly higher than the experimental values. The friction coefficient (0.171) and wear rate (2.31 × 10−7 mm3/N mm) of the composites with 70% Cu-plated graphite flakes are the lowest of the compositions observed in this study. Owing to the lubrication of graphite, the friction coefficient and wear rate decrease with increasing graphite flake content. The thermal conductivity and wear resistance gradually increase when the volume fraction of the Cu-plated graphite flake increase.