纳米SiO_2悬浮体系中的流变、沉降与分维研究  

Rheological, sedimental and fractal study of nano-SiO_2 suspension system

作　　者：安康[1] 孙德军[2] 薛天锋[1] 郭培志[2] 韩涛[1] 胡季帆[1] 

机构地区：[1]山东大学物理与微电子学院,山东济南250100 [2]山东大学胶体与界面化学研究所,山东济南250100

出　　处：《功能材料》2003年第6期721-722,727,共3页Journal of Functional Materials

基　　金：国家自然科学基金资助项目(20043002)

摘　　要：　研究了纳米SiO2悬浮体系的流变特性、沉降过程以及分维特性。从悬浮体系应力随剪切速率的变化曲线,我们发现其流变曲线随着体积分数的变化而改变。通过对不同流型悬浮体系流变曲线的拟合,得出屈服应力值和塑性粘度均随浓度的增加而增加。沉降过程的研究表明,对NH4Cl浓度为1.8mol/L的SiO2悬浮体系,存在两个临界体积分数,重力作用下形成凝胶的临界体积分数为0.1,而上限临界体积分数约为0.54～0.6左右。另外,我们由沉降速度和体积分数的关系计算了该体系较高体积分数下的分维数为D=2.35±0.05。We discuss the rheological properties, sedimentation process and fractal trait of nano-SiO_2 suspensions. From the curves of stress as a function of shear rate for varying SiO_2 volume fractions, we find that the rheological curves vary as the suspension volume fractions change. After fitting the curve of different volume fraction, yield stress and plastic viscosity were given respectively. Results show that they both increased with the increase of volume fraction. The study of the sedimentation indicates that there exist two critical volume fractions for the SiO_2 suspensions when NH_4Cl concentration is 1.8mol/L. The critical volume fraction for gelation in the presence of gravity is 0.1,and the upper critical volume fraction was about 0.54～0.6. Also the variations of the settling velocity along with the volume fractions show a fractal distribution, and the fractal dimension was _D_=2.35±0.05.

关 键 词：纳米SIO2 悬浮体系 流变 沉降 分维 功能材料 

分 类 号：TB34[一般工业技术—材料科学与工程]