Influences of semiconductor oxide fillers on the corrosion behavior of metals under coatings

Semiconductor oxides are widely used as coating fillers, while few studies have focused on the interactions between semiconductor fillers and metal substrates. In this paper, common semiconductor fillers including TiO₂, Fe₂O₃ and Cu₂O were prepared and incorporated into polyvinyl butyral coatings. Localized EIS, EIS, SEM and electrochemical noise analysis were applied to study the corrosion behavior of semiconductor/metal contacts at coating defects. Results revealed that TiO₂ and Fe₂O₃ accelerated the corrosion of metals, while Cu₂O showed no promising effect. Meanwhile, a micro-galvanic corrosion mechanism based on work function difference and oxygen reduction reaction activity was proposed to explain the corrosion-promotion phenomenon.