方镁石、刚玉、尖晶石、莫来石等晶体特异形貌的表征

Characterization of special morphology of periclase,corundum,spinel and mullite

借助于高分辨力仪器研究了方镁石、刚玉、尖晶石和莫来石在不同条件下晶体生长现象,表征了晶体的特异形貌。立方晶系的方镁石和尖晶石自形晶为典型的立方体和正八面体,亦可构成任何其他形状,如连晶化和台阶生长,皆由析晶环境限定。莫来石属斜方晶系,具有长柱状结晶习性,但自形发展常受到环境限制,只有当存在一定液相时析晶(或刚玉与液相发生包晶反应)而呈柱状结晶。莫来石与刚玉组合可以简单共生或以包晶反应形式存在。

The crystal growth theory of periclase,corundum,spinel and mullite in different conditions was studied by means of high-resolution instruments,and the special-morphology crystals were characterized.Periclase of cubic system and euhedral spinel are typical cube and octahedron,and can also form any other shapes,such as joined crystallization and step growth,which are limited by the crystallization environment.Mullite belongs to orthorhombic system and has the long columnar crystallization habit.However,the euhedral development is often restricted by the environment.Mullite crystallizes(or peritectic reaction happens between corundum and liquid phase)into columnar shapes when there is a certain amount of liquid phase.The combination of mullite and corundum can exist in the form of simple symbiosis or peritectic reaction.