流态化气相沉积中FeSi5Cr5.5/SiO2核壳结构的演化过程

以正硅酸乙酯为SiO2绝缘介质前驱体，FeSi5Cr5.5合金球形粉末为基体，研究了流态化气相沉积中FeSi5Cr5.5/SiO2核壳结构的形成时间及演化过程。利用X射线衍射仪、场发射扫描电镜和X射线光电子能谱仪对不同沉积时间下制备粉末样品的显微特征进行了分析，利用振动样品磁强计和四探针电阻率测试仪表征了粉末样品在室温下的磁滞回线和电阻率。结果表明，在流态化气相沉积过程中，从原料FeSi5Cr5.5合金粉末到完全转换成FeSi5Cr5.5/SiO2核壳结构粉末至少需要30 min，且转换过程符合三维岛状形核生长模型。在FeSi5Cr5.5/SiO2核壳结构中分别存在5种氧元素结构和4种硅元素结构，形成FeSi5Cr5.5/SiO2核壳结构后粉末电阻率提高了3~4个数量级，但饱和磁感应强度降低了约9.6%。

Evolution process of FeSi5Cr5.5/SiO2 core-shell structure during fluidized bed chemical vapor deposition

The formation time and evolution process of FeSi5Cr5.5/SiO2 core-shell structure during the fluidized bed chemical vapor deposition were studied with tetraethoxysilane as the precursor of SiO2 insulation and FeSi5Cr5.5 spherical particles as the substrate. The microscopic characteristics of particle samples before and after deposition were characterized by X-ray diffraction, field-emission scanning electron microscopy and X-ray photoelectron spectroscopy. The magnetic hysteresis loops and resistivity of particle samples before and after deposition were measured using vibrating sample magnetometer and four point probe instrument. The results showed that it took 30 minutes at a minimum to completely convert from FeSi5Cr5.5 particles to FeSi5Cr5.5/SiO2 core-shell structure particles according to the three-dimensional island nucleation model during the fluidized bed chemical vapor deposition. There were four and five categories of silicon and oxygen electron structure in the FeSi5Cr5.5/SiO2 core-shell structure. The resistivity of FeSi5Cr5.5/SiO2 core-shell structure particles increased three and four orders of magnitude than that of FeSi5Cr5.5 particles, while the values of saturation flux density declined slightly.