Optical fluorescence spectroscopy for identification of minor oxide phases in alumina scales grown on high temperature alloys

The reference spectra were used as a basis for phase analyses of the oxide scales formed on FeCrAl-alloys during air oxidation at 1200 °C. The spectrometry results of the oxide scales were compared with the data obtained with SEM and XRD. Although identification of the minor alumina scale phases using LIFOS appears to be possible, care should be taken when interpreting the results. The main reason is by far stronger fluorescence from alumina, however other important effects are also discussed, which are responsible for discrepancies between the spectra obtained from “ideal” reference specimens and those from the minor phases in oxide scales.