Phase composition and formation mechanism of NiAl coating on CuCo2Be alloy by plasma spraying

NiAl coating was prepared on CuCo2Be alloy surface by plasma spraying, and the compounds and formation mechanism of NiAl coating were investigated by DTA, XRD and SEM-EDS. The results show that two exothermic peaks were observed by DTA analysis when Ni/Al compound powder was heated in the temperature range of 600 to 671℃, which suggested that two exothermic reactions occurred in this temperature range. The SEM-EDS analysis results revealed that the coating was obviously Layered but the nickel-aluminum compounds were angular. The XRD analysis shows that the compounds in the coating had different types and amounts in different forming stages. The phase formation at the interface and distribution of alloying elements were investigated by XRD and EDS, it was shown that elemental diffusion occurred around the boundary, and micro-metallurgical bonding and mechanical bonding co-existed in the interface.