Nickel Ferrite - Does it have potential as a sidewall material?

A great deal of work has been done on evaluation of nickel ferrite as a material for fabrication of inert anodes, usually as a component in a metal-ceramic composite. Its relatively good resistance to corrosion by cryolite rich baths has led to the suggestion that it might be feasible to use nickel ferrite as a sidewall material. This is a very attractive option, as elimination of the frozen ledge has significant benefits in terms of energy savings and increased productivity. However, very little work has been done to assess its suitability as a refractory material Benchmark testing of the properties of nickel ferrite as a refractory have been conducted as part of a project funded by the CSIRO Flagship Cluster “Breakthrough Technology for Primary Aluminium”. Results of initial work confirm that the nickel ferrite spinel does have a relatively high resistance to attack by cryolite based baths, but the corrosion mechanism is complex, and is not yet understood. However, design of a corrosion resistant grain boundary phase may be the key to development of a successful spinel based refractory.