Depth Resolved XRF and XAS for Enrichment and Oxidation of Mn on Surface of Annealed Fe-Mn Alloys

Abstract

Alloying elements added to steel for improving surface properties such as corrosion resistance are often enriched to the surface of the alloys during annealing at high temperatures. Their behavior depends on difference in their chemical characters and the condition of annealing. In this study, nondestructive depth-resolved analysis of amount distribution and chemical state of alloying element by using X-ray fluorescence analysis (XRF) technique in combination with X-ray absorption spectroscopy (XAS) in order to characterize the enrichment and oxidation of manganese on the surface layers of an Fe-Mn alloy annealed under low oxygen partial pressure. The experiments were carried out using a two-dimensional detector with geometrical arrangement of grazing exit in detection of fluorescence X-ray emitted from sample surface. The results showed that manganese was enriched to surface layers of the Fe-Mn alloys during annealing at high temperatures and formed as manganese oxide. The preferential oxidation of manganese by annealing under low oxygen partial pressure is considered the driving force for their enrichment on the alloy surface.