DEVELOPMENT OF IN-SITU OBSERVATION SYSTEM FOR OXIDE-FILMS FORMED DURING THERMAL-OXIDATION USING RAMAN-SPECTROSCOPY

In-situ observation system for oxidation films using laser Raman spect roscopy was constructed and the growth process of oxide films during t hermal oxidation of Fe-6.5mass%Si alloy at 1073K in O-2, CO2 and CO-CO 2 (P-CO/P-CO2=1) atmospheres was investigated. In-situ Raman spectra o f the oxide films formed in these atmospheres could be obtained using the system with an SN-filter and a chopper unit to reduce the effect o f Rayleigh scattering and thermal radiation. In a CO2 atmosphere stron g Raman peaks of Fe3O4 and alpha-Fe2O3 were observed even in the early stage of oxidation of the alloy, which suggested that the oxidation r ate in the CO2 atmosphere was higher than that in the O-2 or CO-CO2 at mosphere. Since the difference of oxidation behavior in these atmosphe res was not detected by thermogravimetry, the usefulness of the system at high temperatures was confirmed.