Mn对FeCuSiBNb纳米晶合金的高频磁特性和微观结构的影响

通过差示扫描量热仪（DSC）、X射线衍射仪（XRD）、透射电子显微镜（TEM）、磁光克尔显微镜（MOKE）、直流B-H仪和阻抗分析仪等手段研究了Mn元素对FeCuSiBNb合金的热稳定性、高频磁性能、微观结构和磁畴的影响。结果表明：Mn元素对合金的第一与第二晶化温度区间和矫顽力的影响非常小，但可提高合金的高频磁导率和适用退火温度区间。与无Mn合金相比，Mn掺杂合金在10 kHz下磁导率可提高36.5%，且可抑制Fe₃B相的析出。这种良好的高频特性可归因于Mn元素的掺杂降低了纳米晶合金的平均晶粒尺寸，改善了磁畴结构的均匀度，从而降低了钉扎场。

Effect of Mn on High Frequency Magnetic Properties and Microstructure of FeCuSiBNb Nanocrystalline Alloys

The effects of Mn element on the thermal stability, high frequency magnetic permeability, microstructure and magnetic domain of FeCuSiBNb alloys were studied utilizing DSC, XRD, TEM, MOKE, DC B-H loop tracer and impedance analyzer. With the addition of a small amount of Mn, the temperature interval between the first and second crystallization temperatures and the coercivity of the alloys remain almost constant, but the high frequency permeability and the interval of annealing temperature improve significantly. Compared with Mn-free alloys, the permeability of Mn-doped alloys at 10 kHz is increased by 36.5%, and the precipitation of Fe₃B phase is suppressed. This good properties in the Mn-doped alloys can be attributed to the fact that Mn doping reduces the mean grain size, and thus it improves the uniformity of the magnetic domains, which decreases the pinning field of the nanocrystalline alloys.