The low-temperature formation of barium hexaferrites

We have investigated the formation of barium hexaferrites with the compositions BaFe12O19 and Ba2Co2Fe12O22 using precipitation in ethanol. A mechanism for the formation was proposed, based on the results of thermal analysis, X-ray powder diffraction, electron microscopy and the magnetic properties of powders prepared under various precipitation and calcination conditions. The influence of the precipitation conditions on the formation mechanism and the reaction rate was studied. By replacing the water with ethanol the formation temperatures of both compounds were decreased to well below 1000 °C, and the homogeneity of their microstructures was improved. As a result, homogeneous and dense ceramics were obtained at 1200 °C. Precipitation from ethanol solutions proved to be a simple method for the low-temperature preparation of barium hexaferrites.