Nitrogen-induced selective high-temperature internal oxidation behavior in duplex stainless steels 19Cr-10Mn-0.3Ni-xN

Isothermal high-temperature oxidation of duplex stainless steels (DSSs) 19Cr-10Mn-0.3Ni-xN (x = 0.211-0.315 wt.%) at 1100 °C in air has been investigated mainly by scanning electronic microscopy and Raman spectroscopy. High-temperature oxidation resistance of DSSs became worse with the increase of nitrogen content. Self-repairing behavior of local breakaway regions locating in ferrite diffusion layer occurred in DSSs with lower nitrogen content. High-temperature internal oxidation phenomenon preferred to occur in DSS with higher nitrogen content and penetrate into local breakaway regions in ferrite diffusion layer upon the austenite substrate regions as the increased outward diffusion of nitrogen ions.