超声机械法制备纳米二氧化硅及影响因素分析

引言 20世纪,人们发现了纳米粒子具有传统常规颗粒材料所不具备的优良的理化性质和特殊的光、电、磁等特性,从而开始了对纳米粒子的研究,其中包括对纳米粉体粒子基本制备方法的探索1].纳米粉体粒子的制备方法可以归结为两大类:一类是粉碎法,即将宏观物体逐步细化得到纳米颗粒;另一类是构筑法,即从原子、离子或分子出发,通过成核和长大两个阶段来构筑纳米粒子2].构筑法制备纳米粉体粒子所用的能量主要为热能和化学能,需要较高的温度,消耗较高能量,后续的除杂工艺较为繁杂,生产过程中还有可能造成环境污染等.而粉碎法制备纳米粉体粒子,设备投资少、能耗低、效率高、生产能力大、生产过程和产品性能易于控制.

Analysis of factors affecting preparation of SiO2 nanoparticles by ultrasonic-mechanical method

A kind of experimental setup, named as UC-1500, was designed. SiO₂ nanoparticles preparing by ultrasonic-mechanical method were studied, and the effects of ultrasound field, dispersant concentration and grinding time on grain-size and appearance of SiO₂ nanoparticles were investigated. The results showed that the grain-size was smaller and the stability of SiO₂ nanoparticles was better in ultrasonic field.The optimum values of such reaction factors as the space between two adjacent teeth of stirring rad, grinding time, dispersant concentration and the rotating speed of stirring rod were 15 mm, 9 h, 0.09 g•L^-1 and 300 r•min^-1, respectively.With grinding time being the main factor, the effects of dispersant concentration, the rotating speed of stirring rod and the space between two adjacent teeth of stirring rod decreased successively.