燃烧合成铁硅金属间化合物

Fe-Si INTERMETALLICS FABRICATED BY COMBUSTION SYNTHESIS

采用燃烧合成中的自蔓延模式合成了铁硅金属间化合物。用XRD和SEM对掺加不同量KNO3的Fe-Si体系燃烧合成产物进行了研究,试验结果表明,KNO3能够诱导铁硅金属间化合物的生成,当KNO3掺量在20%时,产物完全生成以ε-FeSi和α-FeSi2为主的金属间化合物,ε-FeSi和α-FeSi2共晶相颗粒呈近球状。在溶解-沉淀和流动传质机制的高温条件下,以总表面能的减少为驱动力,物质通过各种传质途径向微粒接触的颈部填充,使颈部逐渐扩大,微粒的接触面积增大;微粒中心相互靠近聚集;同时细小晶粒之间形成晶界,晶界也不断扩大,形成大尺寸晶粒。

Fe-Si intermetallics was successfully fabricated by combustion synthesis. The effect of KNO3 content on product quality was studied by means of XRD and SEM. The results show that KNO3 could induce the formation of Fe-Si intermetallics. When KNO3 content was 20 %, almost all new phases in product were ε-FeSi and α-FeSi2 intermetallics and hypereutectic grains of ε-FeSi and α-FeSi2 were glolular. At high temperature for dissolusion precipitation and the flowing mass transfer, with total surface energy reduction as driving force, the materials were packed at the particle contact pate through mass transfer, making the pate expand gradually, particle contact area increase, particle centers close together and agglomerate, grain boundary form, between tiny crystal grains and the grains grow.