Al对热压MoSi_2材料显微结构的影响

Effects of Al additions on Microstructure of Hot Pressed MoSi_2

本文研究了添加Al对热压MoSi2材料显微结构的影响，提出了过渡气相烧结的概念．结果表明，Al可消除纯MOSi2材料中的SiO2相，生成Al2O3颗粒．Al原子的扩散引起MOSi2晶格膨胀．由于Al蒸汽排除了孤立气孔内影响烧结的残留气体，从而降低了烧结体的气孔率，同时，MOSi2晶格畸变也促进了烧结．Al粉添加量为3．5Wt％时气孔率最低．

The effect of Al additions on the microstructure of hot pressed MoSi2 was studied, and theconcept of t ran s it ion- gas- phase-sintering was proposed. The results indicate t hat t he SiO2 phaseon grain boundary is eliminated by the reaction of Al and SiO2 while the Al2O3 particles areproduced, and the MoSi2 lattice is changed because of the diffusion of Al atoms. Furthermore,the sintering is advanced because of the deformation of MoSi2 lattice and the disappearance ofresidual gas which is replaced by Al vapor in isolated pores, so porosity is reduced. The porosityis the lowest when Al additive is 3.5 wt%.