Structural and corrosion characterization of pulse plated nanocrystalline zinc coatings

The influence of pulse plating parameters on the surface topography, grain size, crystal imperfections and corrosion resistance of Zn coatings has been studied. AFM was applied for surface structure examination, XRD measurements were carried out for texture, grain size and lattice disorder investigation, while the electrochemical techniques were applied for corrosion performance evaluation. Pulse electrodeposition of Zn coatings resulted in ca. threefold reduction in the grain size and ca. fourfold reduction in the corrosion currents in comparison with direct current plated samples. The grain size, lattice imperfection and homogeneity of grain distribution were established to be the main factors determining corrosion behaviour of Zn deposits. Apparently the structure of pulse plated Zn coatings enhances the stability of a passive film on their surface.