Microstructure evolution of cobalt coating electroless plated on SiC whisker during electroless plating and heat treatment

SiCw/Co nanocomposite particles were prepared by electroless plating cobalt on SiC whiskers and the microstructure evolution of the plated coating was investigated by SEM and XRD. SEM images show that growth occurs on the surface of the clusters at the initial stage; as they grow larger, the clusters converge to form a continuous coating, which is actually stacking of cobalt clusters. After heat treated at 500 °C in a hydrogen atmosphere, the cobalt coating transforms from an amorphous to a crystalline state. The thermal stability of SiCw/Co composite is low because of the weak bonding between the substrate and the cobalt coating. The continuous coating aggregates to clusters through surface diffusion during heat treatment.