Surface chemistry and reactivity of skin-passed hot dip galvanized coating

Abstract : GI coatings are covered by a very thin aluminum layer that precipitates after wiping. Anisotropic growing of zinc crystals during solidification induces a strong basal texture in GI coatings. Skin-pass induced changes in GI coating surface chemistry, crystallography and reactivity have been assessed. Local coating analyses have been performed (XPS, TOF-SIMS) in order to describe local effects of roughness indentation during skin-pass on coating characteristics. A laboratory bi-crushing device supported by XRD and EBSD has been used to analyze the aluminum oxide behaviour during deformation and ageing. Reactivity of such surfaces has been tested using fatty acids.