新型Fe72.7Si17B6.8Nb2.6Cu0.9纳米晶铁芯的磁场热处理工艺与软磁性能

为满足高频变压器对铁芯低损耗的需求,研究了新型Fe_72.7Si₁₇B_6.8Nb_2.6Cu_0.9纳米晶铁芯的热处理工艺,探讨了铁芯动态、静态软磁性能随无磁场退火保温时间与施加不同磁场强度的横磁磁场退火时的变化规律。结果表明,不加磁场时,保温时间为60 min时铁芯的损耗最低,为P_{20 kHz/0.5 T}=11.82 W/kg,而其静态软磁性能在保温30 min处于最优状态,H_{c30 min}=1.86 A/m。施加横向磁场后,其直流磁性能剩磁和矫顽力显著降低,H_{c40 mT}=0.64 A/m,而其损耗在磁场强度为50 mT达到最低,为P_{20 kHz/0.5 T}=10.53 W/kg。高频范围内涡流损耗在铁芯损耗中起主导作用,新型纳米晶铁芯经横向磁场热处理后高频损耗大幅降低,同时磁导率表现优异。

Magnetic field heat treatment process and soft magnetic properties of new Fe72.7Si17B6.8Nb2.6Cu0.9 nanocrystalline iron core

In order to meet the requirement of low loss of iron core for high-frequency transformer, the heat treatment process of Fe_72.7Si₁₇B_6.8Nb_2.6Cu_0.9 nanocrystalline iron core was studied, and the variation of dynamic and static soft magnetic properties of the iron core annealed without magnetic field for different time and with different magnetic field intensity was discussed. The results show that when no magnetic field is applied, the core loss is the lowest when the holding time is 60 min, which is P_{20 kHz/0.5 T}=11.82 W/kg, and its static soft magnetic properties is in the optimal state when the holding time is 30 min, which is H_{c30 min}=1.86 A/m. After the transverse magnetic field is applied, the remanence and coercivity of the DC magnetic properties are significantly reduced, H_{c40 mT}=0.64 A/m, and the loss reaches the lowest when the applied magnetic field intensity is 50 mT, which is P_{20 kHz/0.5 T}=10.53 W/kg. Eddy current loss plays a leading role in the core loss in the high frequency range. The high frequency loss of the new nanocrystalline iron core is greatly reduced after transverse magnetic field heat treatment, and its permeability is excellent.