Abstract
Silver (Ag) plating films on Cu alloys are widely used in various electronic and electrical devices due to their excellent electrical conductivity advantageous over other metals, which is advantageous over other metals. In recent years, with the rapid development of HEVs and EVs, the demand for connectors and power devices for high–voltage applications is increasing, and it is expected that highly electrical/thermal conductive silver–plating films with various thicknesses will be essential in the future. In this study, Ag–Graphene composite plating films with high thermal and electrical conductivities were fabricated with the thickness ranging from 5 to 60 µm in bumpy– and smooth–type, and the effects of film thickness and surface morphology on various properties were investigated. Compared with pure silver–plated films, the bumpy particles on the composite films increased with the increase of the film thickness, which is caused by the accumulation of micro–particles with graphene sheets. The bumpy–type composite films exhibited high thermal conductivities of 414–451 W/m K for 40–60 µm thick films using laser flash method, which is around 5 times higher than that of pure Ag films with same thickness. The excellent thermal conductivity can be attributed to the synergistic effect of graphene component with the highest thermal conductivity and the large surface area of the bumpy films, with the latter playing a more important role than the former. The same effect was also confirmed in cyanide composite plating films used in industrialization. Therefore, Ag–Graphene composite films are expected to be promising plating materials for power devices and charging connectors due to their controllable surface morphology and high electrical/thermal conductivity.
