HEXAFERRITE MAGNETIC-MATERIALS PREPARED BY MECHANICAL ALLOYING

The structure and properties of hexaferrites in the form of MFe(12)O(1 9) with M = Ba, Sr and Pb prepared by mechanical alloying and heat tre atment have been studied. Coercivities of 6-7 kOe were measured for Ba - and Sr-hexaferrite powders. The high values of coercivities have bee n associated with small particle sizes (similar to 0.1 mu m) resulting from the mechanical alloying and subsequent heat treatment. High-coer civity anisotropic samples have been synthesized using hot-pressing, w ith remanences of 70-75% of the saturation magnetisation being obtaine d.