Mssbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys,such as SS-304L(1.4306S),Incoloy-800H,Incoloy-825,UBHA-25L,Sanicro-28 and Inconel-690,at 1200℃ exposed in air and steam environments for 400 h.The basic aim was to identify and compare the iron oxides qualitatively and quantitatively,formed during the oxidation of these alloys in two environments.The behaviour of alloy UBHA-25L in high temperature oxidation in both environments indicates that it has good oxidation resistance especially in steam,whereas Sanicro-28 has excellent corrosion resistance in steam environment.In air oxidation of Inconel-690 no iron oxide,with established Mssbauer parameters,was detected. Mssbauer spectroscopy has been used to study the morphology of iron oxides formed during the oxidation of superalloys, such as SS-304L (1.4306S), Incoloy-800H, Incoloy-825, UBHA-25L, Sanicro-28 and Inconel-690 , at 1200 ° C exposed in air and steam environments for 400 h. The basic aim was to identify and compare the iron oxides qualitatively and quantitatively, formed during the oxidation of these alloys in two environments. The behavior of alloy UBHA-25L in high temperature oxidation in both environments indicates that it has good oxidation resistance especially in steam, but Sanicro-28 has excellent corrosion resistance in steam environment. In air oxidation of Inconel-690 no iron oxide, with established Mssbauer parameters, was detected.