Localized Corrosion of 2205 Duplex Stainless Steel with Sigma Phase in the Presence of Pseudomonas Aeruginosa under Alternate Immersion

Abstract In the present work, localized corrosion under the synergistic effect of alternate immersion and σ phase in the presence of P. aeruginosa was investigated, and the mechanism was elaborated. The pitting corrosion was further accelerated by the synergistic effect of σ phase and alternate immersion in biotic medium. The pitting sites on coupons containing σ precipitate under alternate immersion in biotic medium mainly concentrated at the α-γ phase boundaries, which might be closely related with Cr/Mo depletion at the phase boundaries and bigger proportion than that of the σ phase. Furthermore, micro-galvanic corrosion between α and γ phase was inhibited by alternate immersion, resulting in absence of height differences between these two phases.