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以MoO3、Si粉和Al粉为原料,采用机械化学还原法制备了Al2O3-Mo3Si/Mo5Si3纳米复合粉体.利用X射线衍射(XRD)、激光粒度分析仪(LPS)、透射电子显微镜(TEM)、扫描电子显微镜(SEM)和差热-热重分析(DTA-TG)等对复合粉体和球磨过程中粉体的固态反应过程进行表征.结果显示,MoO3-Si-Al混合粉体球磨5h后转变为Al2O3-Mo3Si/Mo5Si3复合粉体,反应为机械诱导的自蔓延反应.球磨20h后,Mo3Si、Mo5Si3和Al2O3的晶粒尺寸分别为27.5、23.3和31.8nm,产物具有纳米晶结构,粉体平均粒度为3.988μm,颗粒呈球形,分布均匀.DTA分析表明,复合粉体在机械化学反应过程中首先发生MoO3和Al之间的铝热反应,之后将发生一系列Mo和Si之间的反应,生成Mo5Si3和Mo3Si.
Al2O3-Mo3Si / Mo5Si3 nanocomposite powders were prepared by mechanical reduction method using MoO3, Si powder and Al powder as raw materials, and characterized by X-ray diffraction (XRD), laser particle size analyzer (LPS), transmission electron microscopy (TEM) , SEM and DTA-TG were used to characterize the solid-state reaction process of the composite powders and the ball milling process.The results showed that the MoO3-Si-Al mixed powders were ball milled for 5h After the ball milling for 20h, the grain sizes of Mo3Si, Mo5Si3 and Al2O3 were 27.5, 23.3 and 31.8nm respectively, and the product had nanocrystalline structure, powder The volume average particle size is 3.988μm, and the particles are spherical with uniform distribution.The DTA analysis shows that during the mechanochemical reaction, the composite powder first undergoes the thermite reaction between MoO3 and Al, and then a series of intermetallic compounds between Mo and Si Reaction, generate Mo5Si3 and Mo3Si.