Oxidation Behavior of Superalloy K52 at 1000℃

The oxidation behavior of cast alloy K52 and its sputtered nanocrystalline coating at 1 000 ℃ in air were investigated by means of XRD,SEM/EDX,TEM and EPMA.The results showed that the sputtered nanocrystalline coating possessed better oxidation resistance than the cast alloy,which was contributed to the formation of α-Al2O3 layer on the sputtered coating,whereas a mixed oxide film of Cr2O3 and TiO2 was formed on the cast alloy.The formation mechanisms of the oxid films were discussed.