Abstract: Surface fractal dimension was employed to describe the topography of flaky powder. DBC algorithm was chosen here to calculate the surface fractal dimension. With this algorithm computer program were tested for six kinds of flaky powder images that were obtained through microscope by digital camera under same resolution. It was found that the values of surface fractal dimension ranged from 2 to 3 and increased with the ruggedness of powder. The tiny pits or ruffles on powder surface made great contribution to the value as fractal dimension. The results obtained show that the surface fractal dimension reflects to some degree the surface roughness. It is valuable to apply the surface fractal dimension to the preparation and application of flaky powder as a description of surface roughness.

Key words: fractal dimension, flaky powder, ruggedness, topography

摘要： 根据片状粉末表面几何特征，提出了用分形方法对其进行描述. 将数码相机拍摄的不同片状粉末的显微照片输入计算机，采用计算分形盒子维的DBC算法对其灰度值进行编程计算，可获得颗粒表面的分形维数. 计算得到的分维数的数值在2~3之间，且粉体表面越不光滑，表现在灰度值的起伏越大，则分维数的数值也越大，与人们视觉上对粗糙表面的观察相吻合. 在一定程度上可有效地反映粉体表面的光滑性，从而为片状粉体表面特性的分析和研究提供了一个新思路.

关键词: 分形维数, 片状粉末, 灰度值, 表面几何特征