Corrosion properties of N-doped austenitic stainless steel films prepared by IBAD

Nitrogen incorporation into 316-L stainless steel was performed by ion beam assisted deposition (IBAD) equipped with one Kaufman ion beam source in Ar/N2 gas mixture and one electron beam source to investigate the effects of Ar/N2 gas ratio on the crystal structure and corrosion resistance of the coatings. An austenitic fcc structure with strong (111) preferred orientation was found for the 316-L films grown under ion bombardment. Corrosion resistance of the N-doped 316-L films were superior or equivalent to the bulk 316-L steel, respectively, when they are tested in 3.5 wt.% NaCl or 0.1 M H2SO4 solutions. Salt spray test results revealed that the corrosion resistance of S45C mild carbon steel was improved significantly by 160% when the N-doped austenitic stainless steel films were deposited, suggesting that the N-doped austenite films are beneficial to anticorrosion properties.