Fundamental Study on Ferrite Manufacturing Process

(Part 4) Grain Growth in Ferrite

Abstract

Microstructures of some typical commercial ferrites (Mn ⋅Zn-, Ni ⋅Zn- and Cu⋅Zn-ferrites) are examined under different conditions of powder preparation and firing. Features and mechanisms of grain growth in each ferrite are discussed based on the basis of experimental results in the previous report. It is shown that the mechanism of grain growth might be predicted from ferrite composition as well as firing conditions. Thus, the coalescence of grains predominates in Ni⋅Zn-ferrite, the grain boundary movement in Cu⋅Zn-ferrite and both in Mn⋅Zn-ferrite. General considerations on effects of additives are given and the effect of Fe₂O₃-addition on Zn-ferrite is presented.