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. 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 2 O 3 melts at 960 ° C. 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.