Sintered samples of nickel ferrite nickel oxide ceramic, usually used as the ceramic phase of cermet inert anode in aluminum electrolysis, were prepared and characterized. The solubilities of NiFe 2O 4 NiO ceramics were measured using an equilibration technique in the Na 3AlF 6 10%AlF 3 5%CaF 2 5 %Al 2O 3 melts at 960 ℃. Electrical resistivity was also measured for NiFe 2O 4 NiO ceramic samples prepared using the usual ceramic technique as function of temperature and content of NiO with an improved pyroconductivity test device, consisting of a specially constructed closed furnace and a Potentiostat/Galvanostat, based on the conventional direct current four probe technique. Results show that, under the experimental conditions, the solubility of Fe from NiFe 2O 4 is 0.06% and Ni from NiFe 2O 4 is 0.008%. The solubility of Fe and Ni from NiFe 2O 4 NiO ceramic is inversely related to each other. The solubility of Ni increases but overall solubility of NiFe 2O 4 NiO ceramics decreases with increasing NiO content. The studied ceramic samples have a semiconductor behavior where electrical resistivity ρ decreases with increasing temperature and the resistivity ρ increases with increasing porosity. The resistivity ρ of NiFe 2O 4 NiO ceramic shows a minimum with increasing the content of NiO at various temperatures.
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