摘要
Mo5Si3-20%Al2O3 （mass fraction） nanocomposite was synthesized by mechanical alloying （MA） of mixture of MoO3,Mo,Si and Al powders.The structural evolutions of powder particles during mechanical alloying were studied by X-ray diffractometry （XRD）,scanning electron microscopy （SEM）,transmission electron microscopy （TEM） and differential thermal analysis （DTA）.Results show that Mo5Si3-20%Al2O3 was obtained after 10 h of milling.The spontaneous reaction of powders takes place in an explosive mode.The crystallite sizes of Mo5Si3 and Al2O3 after milling for 30 h were 36.3 nm and 21.9 nm,respectively.With longer milling time,the intensities of Mo5Si3 and Al2O3 peaks decreased and became broad due to the decrease in crystallite size.Thermal analysis results and XRD analysis results show that the Mo5Si3-Al2O3 nanocomposite powders are very stable during milling （up to 30 h） and heating （up to 1 000℃） and no transformation takes place.
以MoO3粉、Mo粉、Si粉及Al粉为原料,采用机械合金化法合成了纳米Mo5Si3-20%Al2O3(质量分数)复合粉体。采用XRD、SEM、TEM和DTA等对复合粉体在球磨过程中结构变化进行了研究。结果表明:球磨10h后合成的Mo5Si3-20%Al2O3复合粉体,反应以爆炸模式进行。球磨30h后,Mo5Si3和Al2O3的晶粒尺寸分别为36.3nm和21.9nm。随着球磨时间的延长,Mo5Si3和Al2O3的晶粒尺寸变小,衍射峰宽化程度降低。DTA和XRD分析结果表明,复合粉体具有好的热稳定性,球磨30h后再在1000℃退火1h后复合粉体没有发生物相转变。
基金
Project(3ZS061-A25-038) supported by the Natural Science Foundation of Gansu Province,China
