High temperature oxidation behaviour of Ni-Fe-Co anodes for aluminium electrolysis

The oxidation behaviour of ternary NixFeyCoz alloys (where x/y (wt) = 1 and 1.85: z = 0, 10, 30 and 50 wt.%) was studied in air at 800 degrees C. Alloys were found to follow complex oxidation kinetics, with the highest oxidation rates observed for alloys having 50 wt.% Co. Significant improvements in oxidation resistance were achieved by addition of 10 and 30 wt.% Co to the Ni-Fe system. The decrease in oxidation rate was associated with suppression of Fe2O3 formation in preference for (Co,Ni)(x)Fe3-xO4 growth. The results were discussed in light of the materials requirements for inert anodes for aluminium electrolysis. (C) 2011 Elsevier Ltd. All rights reserved.