Surface nanocrystallization of 310s stainless steel and its effect on oxidation behavior

Two techniques, unbalanced magnetron sputter deposition and high-energy short-pulsed plasma discharge, have been used to produce a nanocrystalline surface on AISI310S stainless steel specimens. The average grain size after surface modification was estimated as ∼100 nm by using atomic force microscopy. Cyclic oxidation was performed at 1000 °C with treated and untreated 310S stainless steel specimens. The oxide products formed on the specimens consisted of an outer spinel layer that was rich in chromium, iron, manganese, and nickel, and an inner chromium-rich layer. It was found that the concentrations of iron and manganese in the outer layer of treated specimens were higher, and adherence of the scale was better in the treated specimens. The observed oxidation behavior can be explained by the increase of the creep diffusion rate in the fine oxide scale formed on the nanocrystalline surfaces.