自蔓延热爆合成MoSi2-WSi2复合粉末

以Mo、W和Si粉为原料,采用自蔓延热爆合成制备了不同组分的MoSi2-WSi2复合粉末,并利用X射线衍射仪和扫描电镜对合成产物进行了相组成和产物形貌分析.结果表明:热爆反应产物纯净,MoSi2-WSi2复合粉末中只有MoSi2和WSi2两相存在;颗粒的大小取决于体系的摩尔生成焓,摩尔生成焓越大,颗粒长大越显著;热爆合成反应以Si的熔化为先导,反应机制为熔化-溶解-析出-长大机制.

Synthesis of MoSi2-WSi2 composite powders by thermal explosion mode of SHS

MoSi_2-WSi_2 composite powders with different molar ratios were prepared by the thermal explosion mode of SHS using Mo, W and Si powders. The phase and morphology of the synthesized products were investigated by X-ray diffractrometry and scanning electron microscopy. The results show that there are only MoSi_2 and WSi_2 two phases in the reacted products. The molar formation enthalpy of the system determines the particle size. The bigger the molar formation enthalpy is, the more obvious the particles grow. Thermal explosion synthesis is preceded by melting of Si particles, and it proceeds in a melting-dissolving-precipitating-growing mechanism.