Dissolution Behavior of α and γ Phases of a Duplex Stainless Steel in a Simulated Crevice Solution

The purpose of this study is to clarify corrosion mechanism of a duplex stainless steel (DSS) through dissolution behavior of a ferritic phase and austenitic phase, respectively. A single phase specimen ([alpha] or [gamma] phase specimen) which has chemical composition of each phase of a DSS was prepared by preferential dissolution of the DSS, and dissolution behavior of each phase specimen was investigated. The [alpha] specimen showed a less-noble corrosion potential compared to the [gamma] specimen. The change of the corrosion potential of the DSS was located somewhere between those of each phase specimen. The [alpha] specimen showed a lessnoble active peak compared to the [gamma] specimen. The current density value of the DSS was located between the current values of each phase specimen. It was clearly shown that the corrosion mechanism of a DSS could be described through the dissolution behavior of single phases such as alpha phase and gamma phase.