Characterization of surface oxides on water-atomized steel powder by XPS/AES depth profiling and nano-scale lateral surface analysis

► More than 90% of the powder surface is covered by thin (∼6 nm) Fe-oxide layer. ► Fine oxides rich in Cr, Mn and Si are also present on the powder surface. ► Cr-oxide is present only in the fine oxides and not in the surface oxide layer. ► 2 categories of the fine oxides are recognized according to composition and size. ► In the agglomerates the oxide phases appear as “glued” adjacent particulates.