微米CeO_2的细化及其悬浮液的分散稳定性研究

Refining of Micron CeO_2 and Dispersion Stability of Suspensions

首先使微米CeO2在乙醇中球磨分散,然后向悬浮液中加入一定量去离子水,最后对悬浮液进行超声分散,使用这种方法制备出了分散稳定性较好的微米CeO2悬浮液,探讨了其增强微米CeO2分散稳定性的机制。结果表明:微米CeO2以不同方式分散时在不同比例醇水混合介质中的分散行为各不相同;微米CeO2在纯乙醇中的球磨分散性能最好,其起始分散率可以达到80%左右,而在醇水混合介质中的超声分散性能比在纯乙醇或纯水中的超声分散性能要好,但其起始分散率不高,只能达到20%左右。球磨后加水再超声分散的方法可以显著地提高微米CeO2悬浮液体系的分散性能,其中加入去离子水的最佳体积分数为40%,最佳超声时间为15 min。球磨后加水再超声分散的方法可以进一步打破微米CeO2粉体颗粒间的团聚,使粉体粒径得到进一步的细化,由于去离子水的加入悬浮液体系的表面电位得到了较大提高,乙醇水合团簇的形成使颗粒周围的溶剂化膜变厚。

Slurry of micron CeO2 was prepared by adding water to the ball milling suspensions and then ultrasonic dispersing it for a while and the strengthening mechanisms of dispersion stability were studied.The results showed that ball milling dispersion system of micron CeO2 owned the best stability in pure ethanol agent,the dispersion rate reached as high as 80%,while the best stability of ultrasonic dispersion system turned out to be in ethanol-water mixture,the dispersion rate was 20%.Stability of micron CeO2 slurry was greatly enhanced when water was added to the ball milling suspensions at the volume ratio of 40% and then ultrasonic dispersing it for 15 min,which could break agglomeration,enhance the surface potential of suspensions and thicken the solvation film.