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Notes: High temperature oxidation resistance of alumina-forming materials is connected to thegrowth of dense, stable and protective alumina scales. Depending on temperature, impuritiespresent in the base alloys, presence of water vapour in the oxidizing atmosphere, the alumina scalesare composed of alpha-alumina (which is the stable phase obtained for temperatures over 1000°C)or of transient alumina (γ,θ,δ obtained for lower temperatures). It is generally considered that γ-Al2O3 grows when T〈850°C, that θ-Al2O3 is present for 850°C〈T〈1000°C and that α-Al2O3 isstable when T exceeds 1000°C.The exact role played by transient alumina formation and/or transformation on the high temperatureperformances of alumina-forming materials is not exactly defined. Many works proposed thattransient alumina phases grew during the first steps of the oxidation process and transformed intothe stable phase after further oxidation. The transformation of transient phases in the stable alphaphaseis generally accompanied by a volume contraction of around 14 %.In order to get better oxidation resistance, the formation of transient alumina is not wished, because:1) their growth rate is generally higher than that of alpha-alumina with, as a consequence, a huge Alconsumption, detrimental for the material resistance after long exposures, 2) the change in volumeduring the transformation of transient phases into alpha-alumina can generate stresses in the oxidescale and can weaken its adherence to the underlying substrate, leading to massive spallation.The present study deals with the coupling of different characterization tools in order to preciselyidentify the transient phases grown on FeCrAl materials. The use of scanning electron microscope(SEM-FEG), transmission electron microscope (TEM), Photoluminscescence Spectroscopy(PLS),X-ray photoelectron spectrometry (XPS) and X-ray diffraction at different glancing angles (XRD)on model materials oxidized at two temperatures (850 and 1100°C) could help the identification oftransient phases. These techniques gave a better understanding of the alumina scale growthmechanism