Abstract
This paper reviews recent research at TDK on high performance ferrite magnets. First, new processes forachieving submicron-sized particles, high orientation and high density were studied in detail. As a result, high performance Sr-ferrite magnets with Br=0.44T (4.4kG) and HcJ=320kA/m (4.0kOe) were developed. Furthermore, by means of SiO2-SrO or SiO2-BaO addition, high performance Ba-ferrite magnets with Br=0.43T (4.3kG), HcJ=290kA/m (3.6kOe) were obtained. At the same time, we discovered that it is possible to make equal the shrinkage ratio in the a- and c-axes. Second, (LiFe)ZnW-ferrite and Zn-substituted M-ferrite were investigated. Consequently, LaZn substituted SrM ferrite magnets were developed with extremely good properties, viz. Br=0.46T(4.6kG) and (BH)max=41kJ/m3(5.2MGOe).
