一些溶液法生长的晶体非平衡枝状形貌及其对称性分类

Non-equilibrium Patterns of Some Crystals from Aqueous Solution and the Classification based on Symmetric Characteristics

本文基于一些简单的溶液法晶体生长实验及观察,对非平衡枝状晶体形貌进行了对称性探讨,并提出一种依据晶体的对称性对非平衡形貌进行分类的方案,即:形貌具各向异性且完全受晶体本身的对称性控制,称枝晶;形貌总体具各向同性但局部具各向异性,这种局部各向异性与晶体本身的对称不完全一样,但与晶体本身对称有关,称枝蔓晶;形貌具各向同性,不受晶体本身的对称控制,称密枝(或球粒晶)。这一分类方案对进一步认清非平衡枝状形貌的本质特征、规范一些形貌术语有重要意义。

Based on the observation of the non-equilibrium crystal patterns formed in aqueous solutions, the symmetric characteristics of these patterns were discussed and a classification for the non-equilibrium patterns were proposed. The classification divides the patterns into three categories： dendrite, seaweed-like dendrite and dense branch morphology （DBM） or spherulite. Dendrite displays anisotropy and syuumetry which is the same as the crystal point group. Seaweed-like dendrite displays isotropy in whole scale but anisotropy locally, and this anisotropy is not the same as the crystal point group but related to it. DBM or spherulite displays isotropy which is not related to the crystal point group. It is shown that the crystal symmetry is an important factor to the non-equilibrium patterns, so the classification which was proposed in this paper based on symmetry is significant to realize the property of the non-equilibrium crystal patterns.