摘要
利用同轴圆筒式流变仪分析SiO2微粉悬浮液的剪切流变行为。借助于透射电子显微镜和扫描电子显微镜观察SiO2微粉的显微结构,研究了SiO2微粉的颗粒团聚现象和团聚颗粒在悬浮液中的解聚过程。结果表明:SiO2颗粒团聚过程满足"Southerland ghost"聚集模型,其颗粒结构疏松,影响了悬浮液的剪切流变行为。SiO2悬浮液剪切变稀过程是SiO2微粉团聚颗粒解聚的过程,其流变特性满足Casson模型。该过程分成3个阶段:第1阶段悬浮液三维网络结构被破坏,粒子以颗粒簇的形式存在,悬浮液的黏度迅速降低;第2阶段颗粒簇解聚为颗粒集团,黏度进一步降低;第3阶段颗粒集团不能解聚成原始颗粒,剪切力使颗粒集团内固定的水分子产生流动,黏度缓慢降低。
The shear thinning behavior of fume silica suspension was investigated by a coaxial cylinder rheometer. The micro- structure of fume silica Particles and the phenomenon of particles aggregation were analyzed by transmission electron microscope and scanning electron microscope as well. The shear thinning behavior of fume silica suspension was studied via the decomposi- tion process of agglomerated particles. The agglomeration process follows the Southerland ghost model, and the structure of agglomerated particles is loosen. The loosen structure of agglomerated particles affects the shear thinning behavior of fume sili- ca suspension, The shear thinning behavior of fume silica suspension is correlated to the decomposition process of the aggre- gates, which follows the Casson model. This process is divided into three stages, i. e. , 1） three-dimensional network of sus- pension is destroyed in the initial stage, resulting in the sharp decrease of the viscosity, and the the particle clusters appear; 2） in the second stage, the clusters break into the particles in the suspension; and 3） the particles fail to further break down in the third stage, leading to a high-speed flow carrying off the water in the particles and a decrease of the viscosity.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2014年第3期296-301,共6页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金(51074118)
国家支撑计划(2011BAB03B04)
湖北省自然科学基金(2012FFA103)资助项目
关键词
二氧化硅
悬浮液
剪切变稀
流变性
颗粒团聚
fume silica
suspension
shear thinning
rheological behavior
particle aggregation
