In this research, microstructure and corrosion properties of plasma nitriding and post-oxidation treated AISI 316 austenitic stainless steel have been studied. The plasma nitriding treatment was carried out at 450 degrees C for 5 h in a D.C. plasma setup with a gas mixture of 25% N-2-75% H-2 followed by post-oxidation in gas mixtures of O-2/H-2: 1/3, 1/5, 1/9 and 1/12 for 30 min. The treated samples were characterized by SEM, XRD and roughness testing. Potentiodynamic and cyclic polarization tests were also employed to evaluate the corrosion resistance of the samples. The results showed that plasma nitriding treatment decreases corrosion resistance of the steel substrate. However, post-oxidizing treatment improves both uniform and pitting corrosion resistances of the nitrided specimens. This effect was most pronounced by post-oxidizing at lower O-2/H-2 ratios due to the development of magnetite as a more dense oxide phase over the modified layer. (c) 2013 Elsevier B.V. All rights reserved.