Effect of Photo Irradiation on Corrosion Behaviour and Modification of Passive Films by Ultra-Violet Light

摘要

Modification of passive film by photo irradiation is described as a photo quantum process in the semiconductor thin film. Ultraviolet light irradiation accelerates Cr enrichment in the passive film of Fe-Cr and Type 304 stainless steel, resulting in improved corrosion resistance. The process observed in neutral and acid solution is described in terms of structure change in the passive film induced by photo excitation. Some quantum effects caused by photo excitation are discussed, and possible mechanisms for such photo protection are proposed.