Crystal structure and microstructure of Z-type hexaferrite (Ba, La)Co2Fe24O41 by molten salt synthesis

Abstract

Synthesis of Z-type hexaferrite Ba3Co2Fe24O41 (Ba(3)Z) and Ba1.5La1.5Co2Fe24O41 (Ba(1.5)La(1.5)Z) powders were tried using molten salt synthesis after primary calcination. Ba(3)Z calcined at 1000 degrees C was formed with both M-type and Y-type hexaferrite, and then Z-type was obtained when sintered with molten salt at 1150 degrees C and 1200 degrees C. In the case of Ba(1.5)La(1.5)Z calcined at 1000 degrees C, however, M-type hexaferrite, CoFe2O4 (Spinel phase), and LaFeO3 were synthesized. As a result, Z-type hexaferrite was not synthesized after sintering with molten salt. In addition, the aspect ratio of the particles decreased as the sintering temperature increased with molten salt synthesis. To obtain a single-phase Ba(1.5)La(1.5)Z with a high aspect ratio, it is expected the raw materials have to calcine below the temperature of a spinel phase formation before sintering with molten salt.