Electrical resistivity of NiFe2O4ceramic and NiFe2O4based cermets①
(School of Metallurgical Science and Engineering, Center South University,
Changsha 410083, China)
Changsha 410083, China)
Abstract: NiFe2O4ceramic and NiFe2O4based cermets, expected to be used as the inert anodes in aluminum electrolysis, were prepared and their electrical resistivities were measured at different temperatures. The effects of temperature and composition on their electrical resistivities were investigated. The results indicate that the electrical resistivities of NiFe2O4 based cermets mainly depend on temperature, resistivity of ceramic matrix, composition and dispersion of the metal phase among ceramic matrix. The electrical resistivity of NiFe2O4ceramic decreases from 10.094Ω·cm to 0.475Ω·cm with increasing temperature from 573 K to 1 233 K. The electrical resistivities of NiFe2O4based cermets are greatly lowered, but decrease with increasing the temperature with similar trend compared to that of NiFe2O4ceramic. The resistivities of NiFe2O4based cermets containing 5% Ni, 5% Cu and 5% Cu-Ni alloy are 0.046 8, 0.066 8 and 0.0532Ω·cm at 1 233 K, respectively, which are all acceptable as inert anode materials compared to that of the current carbon anode used for a luminum electrolysis.
Key words: NiFe2O4 cermet; electrical resistivity; inert anode; aluminum electrolysis