IDENTIFICATION OF MO(V) COMMONLY OBSERVED IN PASSIVE FILMS FORMED ON STAINLESS-STEELS

There has been a longstanding debate and controversy in the literature with regard to the determination by XPS of the exact oxidation state of a molybdenum species commonly observed in the passive films of stai nless steel In this paper we have compared both the XPS and ESR analys es of molybdenum oxyhydroxides previously postulated to contain Mo(V) as web as Mo(IV) and Mo(VI). The compositions of these compounds close ly resemble those found in the passive films of Mo-bearing stainless s teel. It has been shown that the same Mo species exhibiting an XPS Mo 3d(5/2) spectrum binding energy value of 230.8 eV is observed to exhib it an ESR spectra having a g factor of 1.921, which corresponds to Mo( V). (C) 1998 John Wiley & Sons, Ltd.