Abstract: SiC-C coatings were deposited on stainless steel substrates using ion beam mixing. In order to improve the element intermixing effect on the coatings and the substrates, thermal treatment and the addition of Cu were used. Secondary ion mass spectroscopy analysis was used to characterize the element distributions for the transition layer between SiC-C coatings and substrates. The diffusion of elements from the coating into substrate happened due to thermal treatment, but its effect on widening the transition layer between C-SiC coating and Fe substrate for the samples of the C-SiC coating on stainless steel substrate is not significant. But, Cu addition and the following thermal treatment can effectively enhance element mixing between the coatings and the substrates.