Atom probe and STM study on stainless steel after vacuum firing

The local elemental composition and morphology of stainless steel surfaces before and after high-temperature bake out (vacuum firing) has been investigated by atom probe (AP) and scanning tunnelling microscopy (STM). The AP depth profiling analysis show significant surface enrichment of nickel after vacuum firing. The surface of AISI 304L stainless steel sheet samples imaged by STM show a significant reconstruction after vacuum firing. Large (1 1 1) terraces with up to 200 nm in width bounded by bunched steps and facets can be observed in the STM micrographs.