Abstract： To clarify the limits of powder activation index often used to evaluate the surface modification effect of inorganic powders, a static mechanical model of ball-shaped particles floating on water surface was proposed. The source of the force keeping inorganic particles surface organized floating on water surface was illustrated in theory. The theoretical limitations of activation index were pointed out. The relationship between contact angle, immersion depth and vertical upward force were investigated through stimulant calculation and theoretical analyses were proved by experiment. The results show that the source of the force which keeps inorganic particles surface organized floating on water surface is the vertical component of surface tension of water acting on the ball-shaped particles floating on water surface. The activation index cannot be used to quantitatively characterize the surface coating effect of inorganic particles.

Keywords: surface tension; activation index; static mechanical model; suspended particles

中图分类号：N34          文献标志码：A

文章编号：1008-5548(2015)03-0080-05

DOI:10.13732/j.issn.1008-5548.2015.03.019

收稿日期：2014-05-20， 修回日期：2014-06-17，在线出版时间：2015-06-24。

第一作者简介：李茂果（1966—），男，硕士，副研究员，研究方向为高分子材料。电话：0816-2494763，E-mail ：limaoguo1966@sohu.com。