High Temperature Corrosion of M-40Cr-0.5Ce Alloys as Inert Anodes in Aluminium Electrolysis

Abstract:

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.

• Periodical: Materials Science Forum (Volume 696)
• Pages: 254-259
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.696.254
• Online since: September 2011
• Authors: Yu Ping Zhu, Ye Dong He, De Ren Wang
• Keywords: Alloy, Aluminium Electrolysis, Corrosion, Inert Anode

References

[1] D.R. Sadoway: JOM. Vol. 53 (2001), p.34.

[2] J. Thonstad and E. Olsen: JOM. Vol. 53 (2001), p.36.

[3] S. Nanmboorthiri, M.P. Taylor, J.J. Chen, M.M. Hyland and M. Cooksey: Asia-Pac J. Chem. Eng. Vol. 2 (2007), p.442.

[4] E. Olsen and J. Thonstad: J. Appl. Electrochem. Vol. 29 (1999), p.293.

[5] L.C. Feng, W.Z. Shao, L. Zhen and N. Xie: Int. J. Appl. Ceram. Technol. Vol. 4 (2007), p.453.

[6] Y.D. He, Y.P. Zhu and D.R. Wang, C.N. Patent 201, 010, 502, 247. 5. (2010).

[7] L. Cassayre, P. Chamelot, L. Arurault, L. Massot, P. Palau and P. Taxil: Corros. Sci. Vol. 49 (2007), p.3610.

DOI: 10.1016/j.corsci.2007.03.020

[8] M. Gluaina and M. Hyland: Corros. Sci. Vol. 48 (2006), p.2457.

[9] V. De Nora and J.J. Duruz, U.S. Patent 6, 998, 032. (2006).

[10] R. Haugsrud, T. Norby and P. Kofstad: Corros. Sci. Vol. 43 (2001), p.283.

[11] N. Birks, G.H. Meier, F.S. Pettit: Introduction to high temperature oxidation of metals 2nd (Cambridge University Press, London 2006).

[12] A. Sterten and O. Skar: Aluminium. Vol. 64 (1988), p.1051.

[13] B. Pieraggi and R.A. Rapp: J. Electrochem. Soc. Vol. 140 (1993), p.2844.

[14] I. Galasiu, R. Galasiu, J. Thonstad: Inert Anodes for Aluminium Electrolysis (Aluminium-Verlag, Dusseldorf 2007).

DOI: 10.1002/9780470947777.ch9

[15] B. Cbattopadbyay, G.C. Wood: Oxid. Met. Vol. 2 (1970), p.373.