铁元素在氮化硅铁中的存在状态

DISTRIBUTION STATUS OF Fe IN FERRO SILICON NITRIDE

用化学分析、XRD,SEM,EDS等检测手段,首次对闪速燃烧工艺制备的新型合成原料———氮化硅铁(FeSi3N4)中铁元素的存在状态进行了研究。结果表明:以小于0.074mm的FeSi75颗粒为原料制备氮化硅铁时,FeSi75颗粒表面的硅原子氮化形成氮化硅包覆层,硅铁受热熔化;随着硅的持续氮化减少,铁含量相对增加,硅的氮化难度加大;最后,铁以Fe3Si和αFe两种形式保留下来,并且主要分布于氮化硅粉体颗粒的内部,并用热力学进行了分析。

The distribution status of Fe in the ferro silicon nitride (Fe-Si3N4) material synthesized by flashing combustion process was analyzed by means of fluorometric measurement, XRD, SEM and EDS. The results show that when the grain size of FeSi75 used in preparing Fe-Si3N4 is less than 0.074 mm, the Si3N4 wrapped layer formed from the nitriding of Si on the surface of FeSi75 grain and ferrosilicon melts. With the continuous decrease of Si by nitrification, the Fe content increases accordingly. Thus the nitrification process becomes difficult to go on and Fe is remained and distributed inside the aggregation of silicon nitride mainly based on the two kinds of state, Fe3Si and α-Fe. The thermodynamic analysis indicates that Fe3Si and α-Fe are the resultant of nitride reaction process.