Oxidation of Fe-Ni Alloys in Air at 700°C, 800°C and 950°C

摘要

The oxidation behavior of Fe-Ni alloys containing 10, 20, 43, 50, 57 and 80 (mass) nickel was studied over the range 700°C-950°C in laboratory air atmosphere using thermogravimetric, XRD and SEM/EDAX techniques. The results showed that some oxidation kinetic curves of Fe-Ni alloys follow the parabolic law, some follow a cubic law, while the oxidation kinetic curves of 90Fe-10Ni is linear. XRD and SEM/EDAX results showed that the oxide scale consists of an outer layer of Fe_2O_3 and an inner layer of Ni-Fe-0 and NiO compound. Ni content in the alloy has an important role for the formation of NiFe_2O_4 oxide. 20Fe-80Ni and 43Fe-57Ni can form NiFe_2O_4 at 700°C-950°C, while 50Fe-50Ni can form NiFe_2O_4 only oxidized at higher temperature of 950°C.