Corrosion Behavior of Nickel Ferrite-Based Ceramics for Aluminium Electrolysis Cells

摘要

NiFe_2O_4-based ceramic materials of different compositions were fabricated from NiO and Fe_2O_3 using a solid-state synthesis technique at elevated temperatures. The materials were tested in a stirred finger test apparatus at 980 °C in synthetic cryolite-based melts. The factors affecting corrosion rates of the materials were investigated experimentally under various conditions, including composition and porosity of the materials, duration of testing, Al_2O_3 content of the electrolytes, bath ratio, CaF_2 addition and test atmosphere. The materials and bath, before and after testing, were characterized by combined XRD, XRF and EPMA. The results indicated that corrosion resistances of the NiFe_2O_4-based ceramic against the baths are very high. The mechanism of corrosion of the material is also discussed.