Correlation of interfacial electrode potential and corrosion resistance of plasma polymer coated galvanized steel. Part 2: Influence of forming induced defects

Stretch forming of galvanized steel coated with ultra-thin SiO2-like plasma polymer films with a thickness of 10–50 nm was performed to study the formation of defects in the films and their relevance for the corrosion protection properties of the coated substrate. It is shown that the interfacial oxygen reduction is already strongly inhibited by SiO2-like films with a thickness of 10 nm. However, uniaxial stretching of these thin films leads to the formation of nanoscopic defects. The influence of nanoscopic defects in the interfacial ultra-thin films on the corrosive de-adhesion mechanisms and kinetics are studied in detail.