Wear behavior of Au–ZnO nanocomposite films for electrical contacts

Abstract

Electrical contact switches require low contact resistance for efficient passage of signals, while withstanding repetitive cycling. Hard gold with alloy additions of Ni, Co, or Ag can increase the wear resistance of Au films, however, this causes a significant decrease in conductivity and alloying elements can segregate during long-term aging leading to property evolution. The current work demonstrates that Au–zinc oxide (ZnO) nanocomposites can create a hard Au coating with a uniform, stable structure under frictional loading. Addition of ZnO particles decreases the grain size and texture of the film by 35 and 40–75 %, respectively, indicating a change in growth behavior of the film. The nanoindentation hardness increased directly with increasing ZnO concentration. Atomic force microscopy examination of wear-tested films demonstrated morphological stability after frictional contact and thus showed the potential for these films to replace current hard Au used on contact terminals.