Alloy design of graded Zn-Cr PVD coatings for corrosion protection of cold formed automotive parts

PVD ZnCr coatings exhibit different metastable crystal structures δ, ζ, Γ depending on the Cr content and the deposition conditions. Here we describe the different mechanical and electrochemical properties of these phases. We show that by introducing an appropriate Cr concentration profile it is possible to produce a ZnCr coating with a thin Γ-phase interface layer optimized for substrate adhesion and a δ-phase matrix with a strong basal …