Impact Of Oxide Additives On The Anodic Performance Of NiFe₂O₄and NiFe₂O₄-0.5NiO

NiFe2O4is a kind of inert anode materials with the high-stability, small-expansion coefficient and excellent corrosion-resistance. In this paper NiFe2O4and NiFe2O4-0.5NiO were prepared by the high temperature solid reaction. NiO and Fe2O3as raw materials were mixed at the ratio of NiO:Fe2O3=1:1and1.5:1were mixed respectively and were ball milled for24h, pressed and sintered at1000℃for10h. The impact of adding V2O5, MnO2and TiO2additives on the composition, morphology, porosity, hardness and conductivity of NiFe2O4and NiFe2O4-0.5NiO were investigated by means of X-ray, SEM, the liquid immersion method, vickers hardness test and AC impedance methods.The result of XRD shows that all the diffraction peaks of the samples are from NiFe2O4or extra NiO and no new phases were detected in the samples with the addition of TiO2and MnO2as well as V2O5. NiFe2O4was of single spinel with cubic crystal. The morphology of NiFe2O4with the addition of0.5%of V2O5, MnO2and TiO2were improved. All the three additives refined the crystalline grain of NiFe2O4. Adding MnO2refined the crystalline grain most obviously, followed by TiO2and then V2O5.The results on the porosity, hardness and conductivity showed that the influence of the three additives V2O5, MnO2and TiO2on NiFe2O4and NiFe2O4-0.5NiO presented different regularities. For NiFe2O4-0.5NiO, the density, electrical conductivity and hardness of samples with the addition of MnO2were superior to those of adding TiO2and V2O5. For NiFe2O4, owing to the liquid sintering of adding V2O5the density and hardness of the samples with the addition of V2O5were better than with the addition of TiO2and MnO2. Adding V2O5increased the conductivity of NiFe2O4.