Effect of particle size and its distribution on the fabrication and magnetic properties of barium ferrite powders prepared from coprecipitated precursors

Six kinds of powder samples with a different particle size and its distribution have been prepared from coprecipitated precursors by light grinding followed by sieving, and calcined in air to form the barium ferrite (BaFe12O19) phase. Correlation between the particle morphology and Fe/Ba molar ratio or magnetic properties has been examined. The results indicated that the powders consisting of coarse particles (100-200 mum) exhibit a single phase of BaFe12O19, and a higher saturation magnetization and coercivity than the powders having fine particles or a wide size distribution. The optimized powders showed a high coercivity of 5.85 kOe and a saturation magnetization of 71 emu/g that are closed to the theoretical values.