High Temperature Corrosion of M-40Cr-0.5Ce Alloys as Inert Anodes in Aluminium Electrolysis
Fe-40Cr-0.5Ce and Ni-40Cr-0.5Ce alloys prepared by vacuum melting have been studied as inert anodes in aluminium electrolysis. High temperature corrosion of these alloy anodes was conducted in cryolite-alumina electrolytes at anodic current density of 0.5 A/cm2, at 800°C and 900°C for 10h respectively. It is found that a Cr2O3 scale was selectively formed on the surface of Ni-40Cr-0.5Ce anode at 900°C, corresponding to excellent corrosion resistance during aluminium electrolysis and higher purity of aluminium product. While a composite oxide film was developed on the surface of Fe-40Cr-0.5Ce anode at 800°C. The formation of Cr2O3 scale is controlled by both of the dissolving rate of Cr2O3 scale in electrolyte and the diffusing rate of Cr in alloys, so the M-Cr alloys require a high content of Cr for inert anodes application.
Toshio Maruyama, Masayuki Yoshiba, Kazuya Kurokawa, Yuuzou Kawahara and Nobuo Otsuka
Y. P. Zhu et al., "High Temperature Corrosion of M-40Cr-0.5Ce Alloys as Inert Anodes in Aluminium Electrolysis", Materials Science Forum, Vol. 696, pp. 254-259, 2011