Interdiffusion coefficients of various cobalt base alloy coatings for Cu/Au system

The interdiffusion coefficients of electrodeposited Co–Mo, Co–P, Co–Mo–P with Cu substrate were studied at temperature ranging from 400 to 800 8C, by micro-profiling method using energy dispersive X-ray spectroscopy (EDS). Chemical interdiffusion coefficients were derived using the Boltzmann–Matano method. At 400–500 8C, the interdiffusion coefficients for Cu/Co–P couples have the same order of magnitude as the Cu/Co–Mo couples. It was found that the interdiffusion coefficients for nickel are higher than that of the cobalt base alloys. The Co–Mo coating becomes poor in term of barrier property when the temperature is above 700 8C.