玻璃包覆铁基微丝的微波电磁特性

本文研究了玻璃包覆非晶微丝FeCoMnSiB在微波频段的电磁特性用x射线衍射技术分析了退火前微丝和不同温度退火后微丝的组织结构分析结果表明，铁基微丝在退火前的组织是由纳米晶和非晶混合组成的，经过465～550℃等温退火1h后，微丝内部组织和电磁特性都发生了改变．把退火前和经过不同温度退火处理过的微丝按一定配比分别散乱混合在石蜡基体里制成同轴样品，采用矢量网络分析仪测试微丝在2GHz到18GHz频段的复介电常数和复磁导率，同时模拟计算不同厚度单层吸波涂层的反射吸收率．由退火前微丝填充组成的涂层中，最小反射率可达一30dB；当微丝经过490℃等温退火后，不同厚度涂层的反射率曲线出现了不止一个吸收峰，而且有的曲线上的吸收峰同时都小于-10dB，吸波的频率范围变宽．结果表明，玻璃包覆铁基微丝可作为电磁损耗材料，具有良好的微波吸收特性．

Microwave Electromagnetic Properties of Glass-Coated Fe-Based Microwires

The electromagnetic properties of glass-coated amorphous microwires, FeCoMnSiB, were studied in the microwave frequency range. The phase structures of as-prepared and annealing microwires were investigated by X-ray diffraction. The result shows that as-prepared Fe-hased microwires consist of both nanocrystais and amorphous structure. The structure and electromagnetic properties of the microwires were changed after annealing at 465-550℃ during 1 h. Coaxial composite samples were prepared by randomly dispersing short microwires, including as-prepared and being annealed at different temperatures, to paraffin wax. The complex perrnittivity and permeability of composites were investigated by coaxial line method with vector network analyzer in the frequency range of 2-18 GHz. In addition, the reflection absorption of monolayer coating with different thicknesses was calculated. The minimum reflectivity of coating made of as-prepared Fe-based nanocrystals microwires was close to -30 dB. After samples annealed at 490℃, the reflectivity curves of coating with different thicknesses appear more than one absorption peak. And the peak values of curves are all lower than -10 dB. The range of useful frequency is wider than that of the as-prepared microwires. The results show that glass-coated Fe-based microwires are electromagnetic loss materials and exhibit excellent microwave absorption performance.