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 isostat ic compacting pressure, and the sintering temperature on a set of phys ical properties for isotropic barium ferrites. The optimum production parameters have been determined, such that S(sp) = 10(3) m2/kg, P = 0. 6-0.7 GPa and T(s) = 1240-degrees-C. A correlation has been obtained b etween the microstresses, the fine crystalline structure parameters an d the electromagnetic properties for sintered specimens as a function of the process conditions. It has been shown that the Fe-57 nuclei sta tes located in the trigonal bipyramid of a magnetic plumbate network o f barium hexaferrites are most sensitive to temperature changes. High isostatic pressures together with other optimized process conditions e nable the isotropic barium ferrites quality to be increased to that of the 7BI215 belt quality.