Development and Mass Production of Low Loss Mn-Zn Ferrite Working at Frequency Higher Than 3 MHz

摘要

Through analyzing the relations between the core loss and the microstructure of Mn-Zn ferrites for power supplies, and by examining the effects of many different additive elements such as CaO-SiO2 on the microstructure and core loss, Mn-Zn power ferrite DMR50 material with extremely low losses than conventional ferrite materials at high frequency was developed. In addition, taking fully into account the mass production condition, a conventional ceramic powder processing technique was employed. The ferrite composition and sintering condition as well as oxide additives were carefully optimized to achieve the desired microstructure for ferrites that can be used at frequency higher than 3MHz. As a result, the core loss at 3 MHz, 10 mT and 100°C is around 300 kW/m3, which is the highest, and is around 60 kW/m3 at 500 kHz, 50 mT and 80°C. Furthermore, the electromagnetic characteristics and the microstructure of this new DMR50 material were also discussed. This material has been successfully produced at large scale.