Pitting initiation on 304 stainless steel in a chloride-contaminated pore solution under alternating temperature conditions

Abstract

Abstract Pitting initiation on 304 stainless steel grades was investigated in alternating temperature pore solutions to simulate pitting on stainless steel rebar in a tropical marine environment. The results suggested that a larger amplitude of alternating temperature heavily doped the passive film, reduced the film’s thickness and increased the (Fe3+ox + Fe3+hy)/Fe2+ox and Cr3+hy/Cr3+ox ratios in the film. Alternating temperatures more significantly degraded the passive film and intensified the pitting sensitivity on the stainless steel when compared with the average temperatures of the alternating temperature cycles. More pitting initiation sites were observed on the samples that experienced the 22–60 °C and 22–70 °C alternating temperature cycles than their counterparts in 50 °C and 60 °C solutions, respectively.