Preparation of Cr hard coatings by ion beam assisted electron beam vapor deposition on Ni and Cu substrates

Hard Cr coatings on Ni and Cu surface were deposited by means of ion beam assisted deposition (IBAD) for the replacement of electroplated chromium in order to avoid the problems of polluting water and hydrogen-embrittlement films from the electroplating. The morphology and mechanical properties of films were examined using SEM, AFM, optical metallographic microscopy, microhardness tester, scratch tester and profile meter. Results showed that adding Al interlayer can improve the adhesion and decrease the residual stress between the coating and substrate due to atom diffusion between the interfaces. The thickness of the interlayer is about 100–200 nm. It concludes that the microhardness of the IBAD samples can reach or even surpass that of the electroplated. It is feasible to obtain Cr hard coatings on some metal substrates by IBAD with optimized equipment and processing.