Influence of uv light on passive behavior of the 304 stainless steel in acid solution

The passive behavior of the passive film on 304 stainless steel in 0.1 M H2SO4 with or without uv light were investigated by potentiodynamic polarization, EIS, Mott–Schottky analysis. The composition of passive film was analysed by XPS. The results indicated that there existed two donor levels in the space charge layer of the passive film, the uv light irradiation could improve the stability of passive film and decrease the passive current destiny. Furthermore, the uv light irradiation might also affect the composition of the passive film, which enhanced the Cr and Ni enrichment in the passive film.

► There existed two donor levels in the space charge layer of the passive film.
► The uv light improve stability of passive film, decrease passive current destiny.
► The uv light enhanced the Cr and Ni enrichment in the passive film.