J. Phys. IV France 07 (1997) C1-61-C1-62
The Dependence of Magnetic and Mechanical Properties on Composition and Processing in Air Fired MnZn FerritesW.M. Dawson
Philips Components Ltd, Balmoral Drive, Southport PR9 8PZ, U.K.
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 Mn2+ and Fe2+ on sintering, and residual stresses introduced via subsequent (re)oxidation upon cooling. In Fe deficient ferrites, properties are determined by the reoxidation of Mn2+, which introduces residual tensile stresses on cooling, so that low strength/high µi are observed. In the Fe excess region, reoxidation of Fe2+ on cooling introduces compressive stresses, resulting in high strength/low µi. Both strength and permeability increase with increasing sintering temperature in Fe excess materials. Cooling in N2 prevents reoxidation, and results in increased permeability for Fe excess ferrites.
© EDP Sciences 1997