摘要
对钠长石(Ab)-钙长石(An)-透辉石(Di)三元体系跨相界线的不同成分点在不同的降温速度条件下快速结晶形成的枝状形貌进行了研究。透辉石为枝晶,斜长石为球粒晶。当降温速度慢于1℃/min后,枝状形貌变为板-柱状形貌(即近平衡形貌)。我们的实验结果中没有观察到如E.Brener和H.Muller等人提出的形貌演化图一样的演化规律。当成分点靠近同结线后,出现两晶共结形成的“中空结构”。通过光学显微镜下测试其光学性质发现,透辉石沿c轴方向延长,斜长石沿a轴延长,与晶体结构中的强键链方向一致,即快速结晶时晶体沿着结构中负离子配位多面体共角顶、共棱形成的强键链方向生长形成枝体。
The non-equilibrium morphology and its crystallographic orientation of Di-Ab-An System at different cooling rates and different phase components were studied. The morphology of diopside is dendritic and the plagioclase is spherulitic. When the cooling-rate is slower than 1℃/min,the morphology is plank or prismatic （near equilibrium morphology）. The morphology evolution in our study is not as the morphology diagram reported by E. Brener and H. Muller. Two phases （diopside and plagioclase） were crystallized together at component 2 and 3, which are close to the phase confines. Through the optical analysis under the polarized light microscope we found that the main branch of the dendritic diopside is along the axis c, aeieular plagioclase along the axis a, which are consistent to the strong bond in their crystal structures. That means the crystal growth is along the strongest bond chains which consist of the growth units of anion coordination polyhedra in the structure at fast crystallization.
出处
《人工晶体学报》
EI
CAS
CSCD
北大核心
2005年第4期642-648,共7页
Journal of Synthetic Crystals
基金
国家自然科学基金(No.40472023)资助项目
