Combined effect of partial calcination and sintering condition on low loss Mn-Zn ferrite

In order to achieve highly densified lower loss Mn-Zn ferrite materials, various powder processing routes have been under investigation. In this report, a lower sintering temperature with lower oxygen partial pressure and proper attrition milling duration are suggested. From the previous study, a partial calcination procedure was studied and an optimum partial calcination level was found. Accordingly, Mn0.71Zn0.22Fe2.07O4 ferrite was prepared by 1/2 calcination with small amounts of CaCO3, SiO2, Nb2O5 and SnO2. The partially calcined ferrites were made by calcining the mixture of the whole amount of ZnO and 1/2 amount of Fe2O3 and Mn3O4 and sintering the mixture of the calcined powders and the remaining 1/2 of Fe2O3 and Mn3O4. Initially, from the 40 min secondary milling and the 1/2 partial calcination, lower temperature (1300 degrees C) sintered samples showed a power loss of similar to 340 mW cm(-3) at 90 degrees C. Secondly, several milling durations showed secondary milling had a more profound effect on magnetic properties than primary milling. The 20 min primary and 90 min secondary milling showed lower core loss around 320 mW cm(-3) at 1300 degrees C and 1250 degrees C, suggesting the sintering temperature could be reduced to 1250 degrees C. Thus, the proper sintering condition of lower oxygen partial pressure at 1250 degrees C was studied. As a result, lower loss with higher density was realized.