An AES analysis of oxide films on iron

The Auger spectra of the iron oxides have been investigated. The relative amplitudes of the Auger lines from oxygen and iron have been determined for FeO, Fe₃O₄, α-Fe₂O₃, γ-Fe₂O₃, and FeOOH. It was found that the amplitude ratio s of the O (510 eV)/Fe (703 eV) lines was, to a first approximation, directly proportional to the ratio of oxygen and iron in the chemical formula. Structure was observed in the spectra resulting from the Fe M_2,3 VV transition. Different spectra were observed for Fe, FeO, Fe₃O₄, Fe₃O₃, and FeOOH; however, the same spectra were obtained for α- and γ-Fe₂O₃.