原位Nb／Nb5Si3复合材料的放电等离子烧结及结构形成机理

Synthesis and Formation Mechanism of Nb/NbsSi3 In-Situ Composites by Spark Plasma Sintering

摘要:

以Nb，Si粉为原料，采用放电等离子烧结（SPS）技术，原位合成了近理论密度的Nb／Nb5Si3复合材料。利用扫描电镜（SEM）、电子探针微区分析（EPMA）和X射线衍射（XRD）分析了材料的组织结构；通过对SPS过程中不同阶段试样的液淬分析，探讨了复合材料的结构形成机理。结果表明，制备的复合材料由Nb和原位合成的Nb5Si3两相组成，Nb以颗粒状均匀分布在Nb5Si3基体上；Nb5Si3是在Nb，Si颗粒的界面开始反应合成的，随着SPS过程的进行，界面反应不断发生，直至反应物中的Si粉完全转变为Nb5Si3。

Abstract:

Taking Nb and Si elemental powders as raw materials,dense Nb/Nb5Si3 composites were successfully fabricated by a spark plasma sintering(SPS)technology.The microstructural features of the synthesized composites were analyzed by OM,SEM,XRD and EPMA.The formation mechanism of the composites was also investigated by a quenching test.The results show that the prepared composites consist of Nb and Nb5Si3 phases,and Nb particles uniformly distribute in the in-situ synthesized Nb5Si3 matrix.During the SPS process,an interfacial reaction occurs between Nb and Si particles to synthesize Nb5Si3 until reactant silicon has been completely reacted.