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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。
Firstly, micron-sized CeO2 was ball-milled in ethanol, and then a certain amount of deionized water was added to the suspension. Finally, the suspension was ultrasonically dispersed, and a suspension of micron-sized CeO2 with good dispersion stability was prepared by this method. The mechanism of enhancing the dispersion stability of micron CeO2. The results show that the dispersion behaviors of CeO2 in different proportions of alcohol-water mixed media are different when they are dispersed in different ways. The milling dispersion of CeO2 in pure ethanol is best, and the initial dispersion rate of CeO2 can reach about 80% The ultrasonic dispersion performance in alcohol-water mixed media is better than ultrasonic dispersion in pure ethanol or pure water, but the initial dispersion rate is not high, only about 20%. The addition of water and ultrasonic dispersion after ball milling can significantly improve the dispersion performance of the system. The best volume fraction of deionized water is 40%, and the optimum ultrasonic time is 15 min. After milling, adding water and then ultrasonic dispersion method can further break the agglomeration between the particles of the micron-sized CeO2 powders so as to further refine the size of the powder particles. Since the surface potential of the suspension system is greatly increased after the deionized water is added, The formation of hydrated clusters thickens the solvation film around the particles.