Growth mechanism of surface scales on Ni-Fe-Cr alloys at 960 °C in air

The oxidation mechanism of Ni-Fe-Cr alloys was studied at 960 degrees C in air. The results showed that an outwardgrowing (Ni,Fe)(3)O-4/Fe2O3 layer and a Cr internal oxidation zone were initially formed on Ni-Fe-10Cr alloy. With increasing oxidation time, a continuous Cr2O3 inner layer was developed between internal oxidation zone and substrate, and subsequently the internal oxidation zone was further oxidized into (Ni,Fe,Cr)(3)O-4 spinel layer. For the Ni-Fe-15Cr alloy, a thin Cr2O3 layer was firstly formed and broken down after 5 h. Then the development process of scale was similar to that on Ni-Fe-10Cr alloy.