Initial stages of cobalt oxidation by FTIR spectroscopy

Abstract

The behaviour of specular reflectance of cobalt oxides on metal has been studied theoretically (CoO/Co system) and experimentally (Co304/Co system; the thin films are obtained by chemical spray pyrolysis) in the infrared region. COO may be identified by a LO mode at 585 cm-I and by a T O mode at 345 cm-l. Co304 is characterized by five bands respectively at 690 (LO), 660 (TO), 605 (LO), 560 (TO) and 390 cm-l. These experimental results allow the characterization of COO and Cos04 grown on metal during the initial stages of thermal oxidation (400-750 OC). For film thicknesses in the range 10-1000 nm, the amounts of COO and Co304 in the duplex structure layers may be estimated by FTIR reflectance spectroscopy. FTIR and XRD studies reveal a cyclic behaviour in the growth of the Co304/CoO/Co system.