On the Nitrogen Diffusion in a Duplex Stainless Steel

Duplex Stainless Steels (DSS) have excellent corrosion resistance properties and poor wear resistance. Plasma nitriding is used to increase the surface hardness, by nitrogen diffusion into the crystal lattice, and to improve wear resistance. In this study, DSS samples were plasma nitrided at temperatures between 350 °C and 500 °C for 240 minutes under an atmosphere of 75% N2 + 25% H2 . Aparent diffusion coefficients, activation energy and pre-exponential constant were calculates using the first law of Fick for each material phase, austenite and ferrite. Nitrogen diffusion in both phases appe...