Corrosion Behavior of Ni-10Cu-11Fe-6Al-1.86Sn Alloy in Molten Cryolite

Development of inert anodes in the Hall–Heroult for aluminum production has been one of the major challenges in recent years. In the present study, the use of Nickel base alloy of Ni- 10Cu-11Fe-6Al-1.86Sn has been studied for using as an inert metal anode in aluminum production industry. Hence, in order to create a corrosion resistant surface oxide layer, the alloy got surface heat treatment. After surface heat treatment at 1000ºC for periods of 30, 70 and 100 hours on the alloy, the behavior of oxidized samples examined in molten cryolite at 930ºC for 70 hours. EDS and XRD studies showed that with increasing time of surface heat treatment, has increased thickness of the oxide layer formed on the samples respectively about 0.95 μm, 35.48 μm and 41.93 μm and after surface oxidation on the samples, in the oxide layers formed the corrosion resistant oxides of NiO, Al2O3, SnO2 and Fe2O3. So that the oxidized sample for 100 hours has the highest corrosion resistance in corrosive cryolite– alumina environment. Finally, the mechanism of corrosion occurred in the corroded samples were studied in the mentioned environment.