Microstructure and hysteresis curves of the barium hexaferrite from co-precipitation by organic agent

This work correlates the magnetic hysteresis curves to the microstructure of the sintered polycrystalline barium hexaferrite discs produced from co-precipitated barium and iron citrates. Citric acid was used as the organic precipitating agent. Thermogravimetric and differential thermal analyses were performed on the co-precipitated product in order to guide its calcination into barium hexaferrite crystals, which was confirmed by means of the X-ray fluorescence and X-ray diffraction. After that, the hexaferrite powder was pressed in a steel die and submitted to firing in air at various temperatures. The final ceramic pieces were characterized by means of scanning electron microscopy and magnetic hysteresis grapher. The obtained results indicate a strong effect of the firing temperature on the microstructure, which in turn affected the magnetic hysteresis curve