Nitriding of Fe–Cr–Ni films by low energy ion implantation

Nitrogen low energy implantation was carried out simultaneously into thin austenitic stainless steel films, deposited by ion-beam sputtering, and bulk samples with the aim to investigate the influence of the grain size and microstructure on diffusion and phase formation. Nitrogen uptake, diffusion and phase formation were investigated using SIMS, XRD and TEM. The diffusion itself is very similar in bulk material and thin films, indicating that the grain size differing by close to a factor of 1000 is not the dominating factor. In contrast, the transition towards CrN precipitates within a martensitic host was only found for the thin films implanted at 360 °C.