Influence of isotropic barium ferrite production conditions on their physical properties

Mossbauer, electromagnetic, and gravimetric studies have been used to examine the influence of ferrite powder specific surfaces, the isostatic compacting pressure, and the sintering temperature on a set of physical properties for isotropic barium ferrites. The optimum production parameters have been determined, such that Ssp=103 m2/kg, P=0.6−0.7 GPa and Ts=1240°C. A correlation has been obtained between the microstresses, the fine crystalline structure parameters and the electromagnetic properties for sintered specimens as a function of the process conditions. It has been shown that the Fe57 nuclei states located in the trigonal bipyramid of a magnetic plumbate network of barium hexaferrites are most sensitive to temperature changes. High isostatic pressures together with other optimized process conditions enable the isotropic barium ferrites quality to be increased to that of the 7BI215 belt quality.