This paper deals with the corrosion behaviour of Ni22Cr10AlY alloy, used as a bond coat in thermal barrier coating systems, exposed in 'pure' SO2 at 1173 and 1273 K. Two types of alloys were used : (i) of high porosity and large grains, (ii) of low porosity and small grains. The oxidation rate of Ni22Cr10AlY in SO2 decreased with decreasing reaction temperature and depended on the type of material. The oxide scales formed during oxidation of Ni22Cr10AlY alloys had complex microstructures and compositions.