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Unreduced low-alloy steel powder containing manganese (≈ 0.3wt.%) were prepared by water atomization,while reduced FeMn pre-alloyed steel powder were obtained after reduction at 970oC in H2 for 2h.The composition,morphology,existing form,distribution of oxides and their evolution during high temperature reduction were analyzed by x-ray diffraction (XRD),scanning electron microscope (SEM) combined with energy disperse spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS).The results show that oxides exist in the forms of γ-Fe2O3,FeO,Mn2O3 and MnO in the unreduced and reduced FeMn powder.In the unreduced powder,γ-Fe2O3 exist in the 40nm outmost layer,while its thickness drops to lower than 10nm after reduction;Mn2O3 exists at any depth of the powder;MnO exists under more than 20nm beneath the surface of the powder.Most oxygen (96.5wt.%) can be reduced after high temperature reduction,with some complex oxides (Fe2O3,Mn2O3)remaining,and the thickness of oxygen-rich layer decreases to 1/22.5 of the original.