Molten Salt Synthesis and Magnetic Properties of BaFe12O19 Hexaferrite

Barium ferrite BaFe12O19 (BaM) powders were prepared by using molten salt method. The preparation conditions of samples were investigated in detail, such as annealing temperature, soaking time, molten salt additive amount and Fe3+/Ba2+ molar ratios. The phase composition, microstructure and magnetic properties of the resultant powders were measured respectively by X―Ray Diffractometer (XRD), Scanning Electron Microscope (SEM) and Vibrating Sample Magnetometer (VSM). Formation of BaM started below 750 in 0.5NaCl+0.5KCl. Single phase BaM powders were obtained while the Fe3+/Ba2+ molar ratios was controlled in the range from 10 to 11.5. The SEM results showed that the grains were regular hexagonal platelets when molten salt additive amount R was controlled in the range from 1 to 3. The resultant powders achieved under condition of Fe3+/Ba2+ molar ratios of 11.5 and calcination temperature of 1000 showed the saturation magnetization up to 71.9A·m2/kg, which was quite close to the theoretical value of 72A·m2/kg.