Abstract
The recent investigation on passivation and passive oxide film of metals was reviewed. The development of analytical techniques and apparatuses are introduced. In the recent two decades, Raman spectroscopy, SPM, and radiation X-ray spectroscopy are widely applied. For the passive oxide films on iron, the composition of γ-Fe2O3- Fe3O4 has been detected. The following themes were discussed; mechanism of the oxide film growth and dehydration of the passive oxide film. Future prospects on the investigation on passivation and passive oxide film were described in which development of the in-situ techniques in sub nm levels with a quite high response was stressed.
