成型压力和脱模剂添加量对FeNiMo磁粉芯磁导率和损耗的影响

Effects of molding pressure and amount of release agent on permeability and loss of FeNiMo magnetic powder core

采用溶胶-凝胶法实现对FeNiMo的SiO_(2)绝缘包覆后制备磁粉芯,考察了硬脂酸锌脱模剂和粉芯成型压力对粉芯磁导率和功率损耗的影响。结果表明,在100 mT/100 kHz条件下,脱模剂的添加对粉芯的磁滞损耗影响较小,对涡流损耗的影响较大。添加适量的硬脂酸锌可提高粉芯的密度和电阻率。随着成型压力增大,粉芯密度逐渐增大,电阻率逐渐降低,导致涡流损耗显著增高。对于不同压力成型的样品,总损耗主要来源于磁滞损耗,这主要由粉芯的矫顽力所决定的。经过优化后的硬脂酸锌添加量为0.25 wt%,成型压力为10 MPa,对应的有效磁导率和总损耗分别为56.8和709.7 kW/m^(3)(100 mT/100 kHz)。相比于其它的SiO_(2)包覆的磁粉芯,经过本实验优化的脱模剂添加量和成型压力制备的FeNiMo粉芯,具有更高的有效磁导率和更低的总损耗。

SiO_(2) insulation coating on FeNiMo was prepared by sol-gel method and magnetic powder core was prepared.The effect of zinc stearate release agent and powder core forming pressure on powder core permeability and power loss was investigated.The results show that under the condition of 100 mT/100 kHz,the addition of release agent has little effect on the hysteresis loss of powder core and great effect on the eddy current loss.Adding an appropriate amount of zinc stearate can improve the density and resistivity of powder core.With the increase of molding pressure,the density of powder core gradually increases and the resistivity gradually decreases,resulting in a significant increase in eddy current loss.For the samples formed under different pressures,the total loss of hysteresis loss mainly comes from the hysteresis loss,which is mainly determined by the coercivity of the powder core.After optimization,the addition amount of zinc stearate is 0.25 wt%,the molding pressure is 10 MPa,and the corresponding effective permeability and total loss are 56.8 and 709.7 kW/m^(3)(100 mT/100 kHz)respectively.Compared with other SiO_(2) coated magnetic powder cores,FeNiMo powder cores prepared by optimized release agent addition and molding pressure in this experiment have higher effective permeability and lower total loss.