SURFACE ANALYSIS OF WATER ATOMISED HIGH CHROMIUM ALLOYED STEEL POWDER BY X-RAY PHOTOELECTRON SPECTROSCOPY

The determination of the surface oxide layer composition is necessary to facilitate the adjustment of the sintering conditions for sufficient removal of the surface oxides for providing strong metal bonding between the metal particles during sintering. Investigation of composition and thickness of the surface oxide was carried out on high Cr-alloyed water atomized steel powder. Analysis of the powder surfaces by X-ray photoelectron spectroscopy showed that powder particles in all cases are covered by a heterogeneous oxide layer, composed of particulate features of thermodynamically stable oxides (Si–Cr–Mn) and homogeneous iron surface oxide layer in between. The thickness of the iron oxide layer is about 4 nm