烧结氧分压对高频MnZn功率铁氧体磁性能的影响

采用氧化物陶瓷工艺制备了高频MnZn功率铁氧体,基于动态磁化理论和损耗分离方法,研究了烧结氧分压对材料显微结构、磁导率和损耗的温度特性的影响。结果表明,随着氧分压的增大,室温下MnZn功率铁氧体的密度d、平均晶粒尺寸D、电阻率ρ和起始磁导率μi逐渐减小,而磁滞损耗Ph和涡流损耗Pe逐渐增大,同时μi-T曲线的二峰位置和Ph-T曲线的最小值所对应的温度逐渐移向高温。相同氧分压烧结MnZn功率铁氧体的涡流损耗Pe和剩余损耗Pr均随温度升高而增大。在氧分压为2%时,高频MnZn功率铁氧体具有最优性能,室温下起始磁导率μi为1175,1 MHz/50 mT时20℃与100℃的损耗PL分别为359 kW/m^3和486 kW/m^3,3MHz/10mT时20℃与100℃的损耗分别为221 kW/m^3和301 kW/m^3。

Influence of oxygen partial pressure during sintering on the magnetic properties of MnZn power ferrites at high frequency

MnZn power ferrites were prepared by conventional oxide ceramic process.The influence of oxygen partial pressure on the microstructure,initial permeability and core losses of MnZn power ferrites have been studied based on dynamic magnetization theory and loss separation method.The results show that,with the increase of oxygen partial pressure,density d,resistivity ρ and initial permeability μi of MnZn power ferrites monotonously decrease at room temperature,while the hysteresis loss Ph and eddy current loss Pe increase.Meanwhile,the temperature of secondary maximum peak of μi-T curve and the minimum hysteresis losses temperature move to higher temperature.With the increase of temperature,Pe-T and Pr-T curve keep rising trend.For the oxygen partial pressure of 2 %,MnZn ferrites with high initial permeability of 1175 at room temperature and core loss of 359 kW/m 3 (25 ℃),486 kW/m^3 (100 ℃) at 1MHz/50mT and 221 kW/m^3 (25 ℃),301 kW/m^3 (100 ℃) at 3 MHz/10 mT were obtained.