Evolution of element distribution in Ni-Cr-Al-Y coating before and after vacuum heat treatment

Ni-based alloy K17 and Ni3Al-based alloy IC-6 were used as substrates coated with Ni-Cr-Al-Y coating deposited by arc ion plating (AIP). The results of the tests show that a few of elements of Co, Ti and Mo etc., which come from substrates were observed in near-surface zones of Ni-Cr-Al-Y coating. It corresponds to the 'sputter' and 'anti-sputter' effect of AIP during deposition process. Atoms Cr distributed from coating to substrate were inhibited by Al contained in alloy K17. In alloy IC-6 with high concentration of Mo, the restraint becomes stronger. During vacuum heat treatment at 1050°C, the activities of various elements were increased, while the resistance of diffusion of Cr by Al and Mo was decreased. A great deal of Cr diffuses from coating to substrate. As a result, the distributions of various elements are not only homogeneity but also close to nominal compositions.