Experimental and modeling studies on the oxygen ingression behavior at the crevices of stainless steels in high-temperature water

Abstract

Experimental

and modeling studies of the oxygen ingression at the crevices of stainless steels were conducted in high-temperature water (288°C). The limiting distance of oxygen ingression, $d_{\lim }$, was defined as the point beyond which the primary surface oxide changed (γ-Fe₂O₃–Fe₃O₄), regardless of crevice gap, oxygen concentration, and time. In situ measurements revealed increased electrical conductivity around the $d_{\lim }$ position indicating ion enrichment due to a differential oxygen concentration cell. $d_{\lim }$ increased with increasing crevice gap, oxygen concentration, and immersion time. Modeling study suggested that oxide layer growth reduced anodic dissolution and slowed oxygen consumption, allowing oxygen ingression with time.