Surface characterization of plasma rotating electrode atomized 30CrMnSiNi2A steel powder

Characterization of surface oxides on atomized steel powder is essential in order to determine the sintering conditions for providing strong metal bonding between the powder particles during consolidation. In the present study, it was the first time to systematically investigate the surface characterization of plasma rotating electrode atomized steel powder. China ultra-high strength low alloy steel 30CrMnSiNi2A powder produced by plasma rotating electrode process (PREP) was chosen as the model material. X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy were performed to methodically investigate the morphology, size, composition and distribution of surface oxides of the PREP powder. The results indicated that the PREP powder surface was covered by dispersed oxide particulates and homogeneous Fe-oxide layer (about 4.6 nm) between the oxide particulates. MnO and FeO were the main forms of the oxide particulates and the Fe-oxide layer, respectively, and a little Fe2O3 existed on the outermost of the Fe-oxide layer. Besides, a small quantity of Cr2O3 and SiO2 existed in local areas of the oxide particulates and the Fe-oxide layer. At last the model of surface oxides distribution of the PREP steel powder was determined.