铁硅合金粉末的改性硅溶胶表面包覆及其磁粉芯性能

Study of surface coating and magnetic properties of Fe-Si alloy powder cores

利用改性硅溶胶包覆液对气雾化Fe-6.5%Si软磁合金粉末进行表面绝缘处理并制备磁粉芯,考察了不同包覆液用量对铁硅磁粉芯性能的影响。结果表明,经包覆处理的合金粉末表面存在均匀的氧化物绝缘层;磁粉芯样品在测试频率范围具有良好的恒磁导率和高频特性;随着包覆液用量的增加,磁粉芯样品的磁导率相应减小、直流叠加性能明显提高,损耗则表现出先减小再增大的趋势。当包覆液用量为1.0 wt%时,样品的恒定磁导率为78,50k Hz、50m T条件下的功耗为170 m W/cm3,直流叠加场为10m T时磁导率百分比为55%,表明适当的粉末表面包覆层有利于获得高性能的铁硅磁粉芯。

Gas atomized Fe-6.5%Si alloy powders were surface-coated with various amounts of modified silica solution, and effects of the coating on the magnetic properties of Fe-6.5%Si alloy powder cores have been investigated. It is found that there exists uniform oxide compounds coating on surfaces of the modified powders. The prepared magnetic cores exhibit stable permeability in the measured frequency range, showing good high-frequency characteristics. With increasing amount of insulating solution, permeability of the samples decreases while the DC-bias property substantially improves. However, the corresponding core loss exhibits a different trend, i.e. decreasing at first and then increasing slightly. The sample corresponging to powders treated with 1.0 wt%of solution possesses a stable permeability of 78, a core loss of 170 mW/cm3 at frequency of 50 kHz under induction of 50mT, and 55%permeability at 10mT of DC-bias field. The results suggest that a proper coating on the powder surfaces can redound to achieve good performances for Fe-6.5%Si alloy powder cores.