Ion nitriding of Fe–30Mn–6Si–5Cr shape memory alloy: I. Nitriding parameters and microstructure characterization

The Fe–30Mn–6Si–5Cr shape memory alloy was ion-nitrided to modify the surface conditions. The phases and microstructures of the nitrided surface were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and glow discharge spectrometry (GDS). Experimental results indicate that the nitrided compound layer consists of Fe0.93Mn0.042N0.028 and Mn4N phases. Higher nitriding temperature and longer nitriding time can have thicker nitriding layer and more quantities of nitrided compounds. [H2]/[N2]=1:99 is found to be an optimal parameter in the ion nitriding of Fe–30Mn–6Si–5Cr alloy in this study.