The behaviour of specular reflectance of cobalt oxides on metal has be
en studied theoretically (CoO/Co system) and experimentally (Co3O4/CO
system; the thin films are obtained by chemical spray pyrolysis) in th
e infrared region. CoO may be identified by a LO mode at 585 cm-1 and
by a TO mode at 345 cm-1 . Co3O4 is characterized by five bands respec
tively at 690 (LO), 660 (TO), 605 (LO), 560 (TO) and 390 cm-1. These e
xperimental results allow the characterization of CoO and Co3O4 grown
on metal during the initial stages of thermal oxidation (400-750-degre
es-C). For film thicknesses in the range 10-1000 nm, the amounts of Co
O and Co3O4 in the duplex structure layers may be estimated by FTIR re
flectance spectroscopy. FTIR and XRD studies reveal a cyclic behaviour
in the growth of the Co3O4/COO/CO system.