An investigation into dissolution behavior of pre-oxidized Ni-6Al-10Cu-11Fe-15Cr nickel base alloy in molten cryolite

Abstract

Purpose -The purpose of this paper was the investigation of corrosion behaviour of Ni-6Al-10Cu-11Fe-15Cr alloy, as a candidate material for inert anodes in aluminium electrolysis industries. Design/methodology/approach -The samples were prepared by casting, and then were oxidized at 1,000°C for 30, 70 and 100 hours, respectively. To determine corrosion resistant of the samples, they were exposed to molten cryolite at 930°C for 70 hours. Then the surface layers were studied. Findings -Results showed that by extension of corrosion time, thickness of oxide layers increases. In addition, it was found that Al2O3 and Cr2O3 are the major oxide compounds that appear on the surface of the sample. Originality/value -In this paper, the Ni-6Al-10Cu-11Fe-15Cr nickel base alloy has been selected to study its corrosion behaviour in molten cryolite as a candidate for inert anodes. It was found out that by addition Al and Cr into the alloy composition, due to formation of Al2O3 and Cr2O3 following oxidation, the substrate was protected from corrosion attacks.