Effect of the Particle Size on the Magnetic Properties of Barium Hexaferrite Bonded Magnets

Abstract

In the present work barium ferrite compression bonded magnet with different particle size were prepared. To start this barium hexaferrite powder was prepared by solid state synthesis method. The calcined powder milled for different time to obtain the powder of different size. The chosen ball milling times were 1 h, 2 h, 3 h and 4 h. The particle size distribution was studied by mechanical sieving of powder. The prepared powders were mixed with epoxy resin and pressed in cylindrical die using hydraulic press. Phase and microstructural characterization was carried out by X-ray diffractometer and scanning electron microscope. XRD pattern shows the single phase barium hexaferrite. It is found that with increasing milling time the crystallite size decreases. From the SEM images it is found that the average particle size of powder decreases from 0.7µm to 0.5µm as the milling time increases. The magnetic properties were measured by vibration sample magnetometer. The result shows as the milling time increases the coercivity increases. The saturation magnetization remains same for all the bonded magnets.