The Dependence of Magnetic and Mechanical Properties on Composition and Processing in Air Fired MnZn Ferrites

The relationship between magnetic and mechanical properties has been studied as a function of composition, atmosphere and temperature for a series of MnZn ferrites. When processed in air, strength and permeability are critically dependent upon the formation of Md+ and ~ e ' + on sintering, and residual stresses introduced via subsequent (re)oxidation upon cooling. In Fe deficient femtes, properties are determined by the reoxidation of Mn2+, which introduces residual tensile stresses on cooling so that low strengthhigh h are observed. In the Fe excess region, reoxidation of ~e '+ on cooling introduces compressive stresses, resulting in high strengthhow h. Both strength and permeability increase with increasing sintering temperature in Fe excess materials. Cooling in Nz prevents reoxidation, and results in increased permeability for Fe excess femtes.