自蔓延高温合成WSi_2-MoSi_2复合粉体的制备、组成与形貌分析

Preparation,composition and morphology of WSi_2-MoSi_2 composite powders obtained by high-temperature self-propagating synthesis method

为了研究金属W加入量对自蔓延合成WSi_2-MoSi_2复合粉体组成和形貌的影响,以d50分别为5.67μm的Si粉、3.15μm的Mo粉和2.13μm的W粉为原料,按照化学式(Mo1-xWx)Si_2中W的物质的量分数分别为10%、20%、30%和40%,采用自蔓延高温合成方法制备了不同W含量的WSi_2-Mo Si_2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:W粉的添加会降低反应的绝热温度。通过对产物最强的衍射峰进行分峰拟合,证实在本试验中Mo Si_2和WSi_2是以两个单相的形式存在;WSi_2-Mo Si_2复合粉末形貌呈近球形颗粒的聚集状态,并随着W加入量的增加,合成产物的颗粒尺寸有变小的趋势。

To investigate the influence of the W addition on the composition and morphology of WSi2-MoSi2 composite powders,Si powder （d50 =5.67 nm） ,Mo powder （d50 =3.15 nm） and metal W powders （d 50 = 2.13 nm） were taken as starting materials to prepare composite powders with different W contents （10% , 20% ,30% ,40% ,by mole） according to the chemical formula of （Mo1_xWx）Si2 by a self-propagating high- temperature synthesis （SHS） method. The phase composition and morphology of the final powders were investigated by X-ray diffraction （XRD） and scanning electron microscope （SEM） characterization. The re-suits show that the W addition reduces the adiabatic temperature of the reaction;the differenating and fit-ting of the strongest diffraction peak of the products prove that MoSi2 and WSi2 exist as two separate phases;the morphology of the WSi2-MoSi2 composite powder is spherical particle aggregation＇s the W addi-tion rises,the particle size of the powder decreases.