Chipping Resistance of Zn - Ni Alloy Electroplated Steel Sheet

Zinc-Nickel alloy coatings have been used to improve corrosion resistance for automobile bodies. It has been reported that the coated layer with γ phase in the range of 9-17wt% Ni provides superior corrosion resistance. However, this improved corrosion resistance normally accompanies easy delaminating of the coated layer, even by the tiny foreign impact, such as small stones of the road. In this study, the chipping resistance of 9-19wt% Ni-Zn electroplated steel sheets was examined, in terms of Ni content in the coated layer, and the influence of testing temperature. SEM fractographs and metallographs were employed to discuss the coating morphology and microstructures in the as-deposited and chipping tested conditions.