J. Mater. Sci. Technol. ›› 2022, Vol. 107: 216-226.DOI: 10.1016/j.jmst.2021.08.028

• Research Article • Previous Articles     Next Articles

Evaluation of Ni-Fe base alloys as inert anode for low-temperature aluminium electrolysis

Wei Wei, Shujiang Geng*(), Fuhui Wang   

  1. Shenyang National Laboratory for Materials Science, Northeastern University, No.3-11 Wenhua Road, Shenyang 110819, China
  • Received:2021-06-04 Revised:2021-06-04 Accepted:2021-06-04 Published:2022-04-30 Online:2022-04-28
  • Contact: Shujiang Geng
  • About author:* E-mail address: gengsj@smm.neu.edu.cn (S. Geng).


Isothermal oxidation behaviors of Ni-Fe (wt.%) and of the same alloy with additions of 10 and 15%Cr alloys in the air at 800 °C and 900 °C and their anodic behaviors in aluminum electrolysis system at 800 °C were evaluated. The composition morphologies of oxide scales were characterized by XRD, SEM, and EDS. Results show that the scales formed on Ni-Fe alloy at both temperatures consisted of an inner (Ni,Fe)3O4 layer and an outer Fe2O3 layer. For Ni-Fe-10Cr alloy, an external (Ni,Fe)3O4/Fe2O3 layers and an internal oxidation zone were formed at 800 °C, while a continuous Cr2O3 layer forms at the internal oxidation zone/substrate interface at 900 °C. A multilayer structure oxide of Cr2O3/(Ni,Fe,Cr)3O4/(Ni,Fe)3O4/Fe2O3 was formed on Ni-Fe-15Cr alloy at 800 °C, while at 900 °C the Fe2O3 becomes discontinuous disperses in the (Ni,Fe)3O4 layer close to the surface. Increases in oxidation temperature or Cr content for Ni-Fe-Cr alloys promote the growth of the inner Cr2O3 layer and simultaneously reduce Fe2O3 content. After 4 h of electrolysis at an anode current density of 0.25 A cm -2, the oxidation resistance of Ni-Fe-15Cr anode is superior to the Ni-Fe anode.

Key words: Alloy, Inert anodes, Selective oxidation, High temperature corrosion