Fabrication and Composition Investigation of WSi_2/MoSi_2 Composite Powders Obtained by a Self-Propagating High-Temperature Synthesis Method

摘要

In this paper, MoSi_2/WSi_2 composite powders with different phase compositions were fabricated via a selfpropagating high-temperature synthesis (SHS) method. The influence of initial raw material compositions on the formation and the phase evolution of the MoSi_2/WSi_2 composite powders were investigated. Thermodynamic analysis indicated that the incorporation of W in the starting materials decreased the adiabatic temperature during the SHS reaction, and self-sustainable reaction can be hindered when the W content reached up to 40%. For samples with raw material composition of (1 − x)M_(o·x)W·2Si (X = 0.10, 0.20, 0.30, 0.40), composite MoSi_2/WSi_2 powders can be prepared, which were confirmed by the existence of two fitted peaks that can be assigned to tetragonal MoSi_2 (103) and WSi_2 (103) crystallographic planes in the XRD fine scan patterns. SEM images also confirmed the existence of two maxima in particle size distributions for samples with high Waddition contents. The formation of MoSi_2/WSi_2 composite powders and the evolution of composite phases reported in this paper may provide an effective strategy for the synthesis of silicide based composite materials.