Magnetic properties and mechanical strength of MnZn ferrite

From MnZn ferrite ("6H20" of FDK production), cores having grain size of ab out 8 similar to 10 mum were produced by controlling the calcination temper ature, after-calcination milling time, and sintering conditions. The ferrit e powder production conditions and core microstructure were examined to det ermine their effects on the magnetic properties and mechanical strength of MnZn ferrite cores. A tendency of core loss to decline with a decrease in g rain size was confirmed. Strength increased also with a decrease in grain s ize. Thus, a relation similar to that between strength and fracture toughne ss in the Equation of Griffith-Irwin was noted. By these findings, it has b ecome possible to produce MnZn ferrite cores with lower loss and greater st rength.