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采用SEM、EDS等手段研究了闪速燃烧合成的氮化硅铁及其原料FeSi75的组成、结构,并结合闪速燃烧合成工艺和热力学分析,揭示氮化硅铁中FexSi粒子的形成机理.结果表明:在以74μm的FeSi75氮化制备氮化硅铁过程中,金属硅和ξ(FeSi2.3)相中部分硅氮化为氮化硅,而氮化硅铁中FexSi粒子则来源于ξ相的氮化;当ξ相被氮化到其中的[Si]摩尔分数降低近25%时,[Si]的活度aSi趋于0,氮化趋于平衡,ξ相中不能被继续氮化的部分即为FexSi粒子,其Fe∶Si原子比例大约为3∶1;FexSi粒子的大小、均匀分布状况与ξ相颗粒粒径大小及分布状况有关.
The composition and structure of ferrosilicon nitride and its raw material FeSi75 synthesized by flash combustion were studied by means of SEM and EDS, and the formation mechanism of FexSi particles in ferrosilicon nitride was revealed by combining flash combustion synthesis and thermodynamic analysis. It is shown that during the nitriding of ferrosilicon with 74μm FeSi75, silicon nitride is partially nitrided to silicon nitride in silicon and ξ (FeSi2.3) phase, while FexSi in ferrosilicon nitride is derived from ξ phase ; When the [Si] mole fraction of the ξ phase nitrided into it is reduced by nearly 25%, the activity of [Si] aSi tends to 0, the nitriding tends to be balanced and the ξ phase can not be continuously nitrided Part of FexSi particles, the Fe: Si atomic ratio is about 3: 1; FexSi particles size, uniform distribution and ξ phase particle size and distribution.