Abstract

Al first, the ferric oxide was ground in a roll mill, and then this product was submitted to planetary ball milling. Separately, the milled iron oxide samples (ultra-finely milled) wc.rc pul mixed with stoichiometric amounts of barium carbonate and doping elements and then calcined (1) at l35O°C during 4 hours. That sample coming from ultra-fine milling prior to calcination was again submitted to final ultra-fine milling in a planetary ball mill. The doped barium hexaferrite final powder was granulated through spray drying and die-pressed into discs, which were subseqüchtly sintered at 135O°C. These sintered pieces were characterized by scanning electron microscopy, X-ray diffraction, (2) and magnetic characterization.