Investigations on the passive and pitting behaviors of the multiphase stainless steel in chlorine atmosphere

Abstract

Multiphase stainless steel is a kind of stainless steel that obtains good mechanical properties. Nevertheless, the passive and pitting behaviors of multiphase stainless steel remain inadequately elucidated. This study aims to investigate the passive and pitting behaviors of multiphase stainless steel by employing Auger electron spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and electrochemical techniques. The conclusions drawn from this research are as follows: The main constituents of the passive film on multiphase stainless steel comprise FeO, Fe2O3, Cr2O3, and Cr(OH)2. The passive film on the martensitic phase displays largest thicknesses. The Cr content in the passive film of the ferritic phase is highest. Particularly, the passive film on the (111) orientation of martensitic phase is thicker than that on the (001) and (101) orientations. Pitting corrosion in multiphase stainless steel primarily initiates at phase interfaces and subsequently extends into the ferritic phase.

Keywords

• Passive film
• Pitting corrosion
• Multiphase stainless steel
• Auger electron spectroscopy