高频高直流迭加Mn-Zn铁氧体材料的性能

摘要

The performance and size of an electrical device is mainly determined by the ferrite core with high DC-bias property and low power loss at high frequencies.Based on our previous study on DMR50 material,DMR50B Mn-Zn ferrite material with a better DC-bias property and with a lower power loss at high frequencies up to 3MHz was developed employing a conventional ceramic powder processing technique and low temperature sintering technology.The core loss is around 200kW/m3 at 3MHz,10 mT and 100℃,and around 20kW/m3 at 700kHz,30mT and 100℃.Its cutoff frequency fr is（4MHz,in accord with the result calculated by Snoek＇s Law,and can be explained by proper grain boundary model.Its Bm is 430mT at 100℃,and HDC=100A/m.Its average grain size D is 2.40μm,which is smaller than the single domain size 3.8μm needed for Mn-Zn ferrite.Its better properties are derived from densely sintered ferrite with more homogeneous fine-grained microstructure.%高工作频率、低损耗和高直流迭加磁芯是决定电子器件体积和性能的主要因素。在开发出DMR50材料的基础上,采用低温烧结技术,用传统的陶瓷法工艺制备了可使用至3MHz的低功耗高直流迭加Mn-Zn铁氧体材料DMR50B。在3MHz,10mT和100℃时材料的功耗在200kW/m3左右,在700kHz,30mT和100℃时只有20kW/m3左右。材料在100℃时的Bm=430 mT,HDC=100A/m。材料的截止频率fr在4MHz左右,与用斯诺克定律计算出的结果相符合,并可用晶界模型解释。材料优异的性能是由其小于单畴临界尺寸3.8μm的均匀细晶粒结构（D=2.40μm）决定的。