Corrosion Behavior of a Nickel-Free High-Nitrogen Stainless Steel with Hydrogen Charging

Hydrogen permeation usually facilitates the corrosion of stainless steel remarkably. Herein, the corrosion behavior of a nickel-free high-nitrogen stainless steel (HNSS) containing 0.96 wt.% nitrogen with hydrogen charging is investigated by means of electrochemical measurements and x-ray photoelectron spectroscopy surface analysis. The results show that hydrogen charging not only increased the passive current density but also increased the pitting potential of HNSS. The increase in passive current density was attributed to the increased carrier density, depleted Cr content, and decreased O2-/OH- ratio in the passive film, while the increase in the pitting potential resulted from the enrichment of N element in the passive film and the replacement of Ni with Mn in HNSS.

Automated summary

The research found that hydrogen charging not only increased the passive current density of high-nitrogen stainless steel, but also increased its resistance to pitting. This was attributed to the increase in carrier density, decrease in chromium content, and decrease in the ratio of oxygen ions to hydroxide ions in the passive film.