IGCC recovery boiler materials are subject to severe corrosion in environments composed of a gas mixture (CO-H-2-H2O-CO2-H2S) and vanadium-containing fly-ash resulting from the combustion of oil residues. This paper presents a study of the corrosion behaviour of two Fc-Ni-Cr austenitic alloys in a typical IGCC environment at 400 degreesC. The alloy composition influences the vanadium incorporated in the corrosion scales during the test, which affects the scale growth process. The valence state (determined by micro-XANES) and the amount of the incorporated vanadium is modified by a subsequent air flow at 400 degreesC.