Influence of PbO on microstructure and properties of a NiZn ferrite

Densification and microstructure development in PbO-doped NiZn ferrite have been studied with special emphasis on the effect of the PbO amount. Pure Ni0.36Zn0.64Fe2O4 ferrite powder requires a sintering temperature of about 1300 °C to achieve a density of 5 g/cm3. A small amount of PbO added to the ferrite powder reduces its sintering temperature by about 200 °C, without degrading material properties. A sintered density of 4.9 g/cm3 was achieved at 1100 °C with 1.2 wt.% PbO addition. Densification has been found to occur by liquid phase sintering. The PbO addition was also found to prevent exaggerated grain growth by hindering grain boundary motion.