Comparison of in-situ low-pressure oxidation of pure iron at room temperature in O2 and in O2/H2O mixtures using XPS

Abstract Low-pressure (10 -6 -10 -8 Torr) in-situ oxidation of Fe by O 2 and O 2 plus H 2 O at room temperature has been studied by X-ray photoelectron spectroscopy. Non-linear least-squares fitting routines are applied to determine the thin oxide film composition. For exposures from 1 to 10 4 L pure iron oxidation leads to a Fe 2 O 3 layer on top of FeO. No or little FeOOH formation is observed. Some OH - is adsorbed at the surface. Exposure to a mixture of H 2 O + O 2 (50/50) does not influence the composition of the oxide film.