Rainbow fringes around crevice corrosion formed on stainless steel AISI 316 after ennoblement in seawater

Abstract

The crevice corrosion occurrence probability of stainless steel (SS) AISI 316 was increased under ennoblement condition due to chemically added H2O2 into seawater. The H2O2 was used to simulate the important factor causing ennoblement in natural marine biofilm. Morphology of the crevice corrosion was observed using an incident‐light source microscopy. Some interesting “rainbow” fringes were observed around micro‐crevices. The mechanism was discussed from the ions diffusion and potential distribution during the crevice formation. This result shows that under ennoblement condition the colored fringe is a distinct characteristic of the morphology of localized corrosion for stainless steel.

Susceptibility of 316L stainless steel to crevice corrosion in submersible solenoid valve

“…The colors from inner to outer fringe are yellow, purple, green and yellow. Similar phenomenon has been reported [26]. Colored fringes around the crevice corrosion appear as a result of the interference of incident light on the deposited film, which is formed due to hydrolysis of the corrosion ions of reaction with anions in artificial seawater on 316L stainless steel surface [26,27].…”