Abstract
A duplex structure, in which some of large grains coexist with many small grains, has been observed in sintered Mn-Zn-ferrites when used the starting materials comprised of small powder and calcined at higher temperature. The large grains were suddenly formed through the nucleations after some induction periods. It was found that Avrami equation could be applied to the relation between net volume of large grains and sintering time. On the other hand, the duplex structure was also observed in the same ferrite when a small amount of Bi2O3 or V2O5 was added to the starting materials and sintered at the same condition. The mag-netic properties of the specimen having duplex structure were superior in B50, Br and permeability, and inferior in Hc and Curie temperature to those of the specimen havi,
