羰基铁纤维的磁场诱导制备及其微波电磁特性分析

Microwave electromagnetic characterization of carbonyl iron fibre prepared by magnetic-field-induced chemical decomposition

羰基铁热分解产生的铁原子在外加磁场的作用下形成羰基铁纤维。对羰基化合物气化速率、保护气氛流量、分解温度和外加磁场强度等因素的调控,制备出铁含量在90%~98%可调、直径在亚微米到微米(200nm^10μm)及长径比可控的羰基铁纤维。将羰基铁纤维与石蜡制成同轴样品,采用矢量网络分析仪测量了羰基铁纤维的微波电磁参数。结果发现羰基铁纤维在2~18GHz范围内具有高磁导率、高磁损耗和良好的频响特性。两种羰基铁纤维在2GHz处,磁导率实部为5.2和3.5,虚部为2和1.5,所对应的共振频率分别为3和6GHz。通过对羰基铁纤维中碳含量及长径比的调节,可控制纤维的磁导率和共振频率。

The atoms of Fe obtained by chemically decomposing Fe（CO）5 vapor could form fibre in magnetic field. The growth mechanism of iron fibre had been studied. Carbonyl iron fibre with different Fe content （90%-98wt%） and diameter （200nm-10μm） had been fabricated by adjusting fibre growth factors, such as velocity of Fe（CO）5 vapor and protective gas, temperature of chemical decomposition and magnetic field strength. So the diameter of carbonyl iron fibre could be controlled from micron to sub-micron. The fibre-wax composite was homogeneously mixed and pressed into coaxial sample. The electromagnetic properties of the composite were measured with the transmission and reflection coaxial line method using a network analyzer. The result shows that carbonyl iron fibre possesses high permeability, high magnetic loss and good frequency dispersion in the frequency range from 2GHz to 18GHz. The real permeability of two kinds of carbonyl iron fibres are 5.2 and 3. 5, and the imaginary part are 2 and 1.5, respectively. The corresponding resonance frequencies for the fibres are 3GHz and 6GHz. The different content of carbon and the various aspect ratios of fibres can adjust their com- plex permeability and resonance frequency.