Synthesis of ultrafine particles of barium ferrite by chemical coprecipitation

A new method to synthesize barium hexaferrite by chemical coprecipitation is described. A mixed precursor was precipitated by addition of a barium salt to a strongly alkaline ferrate (VI) solution. The precursor yielded barium hexaferrite on heating for 6 h at 800 degrees C; partial transformation was evident even at lower temperatures, from X-ray patterns and Mossbauer spectra. Scanning electron microscopy of the powders fired at 800 degrees C, showed that the particles were less than 0.5 mu m in diameter.