摘 要讨论了 NaCl 溶液在不同初始浓度、不同温度和不同基底时结晶的表面形貌。利用原子力显微镜从介观尺度上对不同影响因素下 NaCl 溶液结晶样品进行了观察，利用图像处理软件 Image-pro Plus 处理扫描图像，分析了这几种因素对 NaCl 溶液结晶过程的影响，并对其成形机制和分形维数进行了探讨。讨论结果表明，初始浓度越低，结晶分形花样越倾向于生成由细小的晶体颗粒组成的树枝状结构。随着初始浓度的增大，结晶分形花样聚集程度越来越高，生成的枝叉状结构越来越大，并且结晶中有许多立方体结构。比较结晶花样的分形维数，发现较低初始浓度结晶的分形花样的分形维数与 Koch 曲线类似，较高初始浓度结晶的分形花样的分形维数符合扩散受限聚集（Diffusion-limited aggregation，DLA）模型的结果。随着结晶初始浓度的增大，分形维数逐渐增大。温度影响了结晶的速率，结晶速率大，则结晶中心增多，晶体长得细小，且往往长成针状、树枝状。反之 ，结晶速率小，晶体长得粗大。表面平整度影响着结晶的表面形貌。而且，表面的平整度会影响溶液的流动，从而影响 NaCl 晶粒的聚集行为，对分形花样的形成起到一定的作用。关键词：NaCl 溶液；结晶；分形维数；扩散受限聚集机制AbstractThe surface topography of sodium chloride solutions crystallization was studied in different initial concentration, different temperature and different basement.The surface topography of sodium chloride solutions crystallization samples were observed from meso scale underdifferent affecting factors by atomic force microscope,and using the Image-pro Plus to processing the scan images.Analyzing the influence of the several factors to the process of sodium chloride solutions crystallization,the forming mechanism and the fractal dimension were discussed.The results of the study show that the lower of the initial concentration of the sodium chloride solutions, the more tend to generate dendritic structurefractal pattern consisting ofsmall crystal particles. Along with the increase of the initial concentration of the sodium chloride solutions,theaggregation degre...
