On the growth mechanism of sodalite single crystals grown by the hydrothermal method on single crystal seeds coated with informative informative interfacial layers

Abstract

The growth mechanism of the early formation stages of sodalite single crystals grown by the method of hydrothermal synthesis on single crystal seeds coated with interfacial layers of polycrystalline silver has been studied a t an electronmicroscopic scale. Coating with interfacial layers leads to a very weak adhesion between the overgrown single crystal and the surface of the interfacial layer on top of the seed, thus providing a unique possibility of detaching the overgrown single crystals from seeds and investigating the very early crystallization stages by the morphology of the growth surface. I n local microregions of seed surfaces coated with interfacial layers discrete particles arise differing from one another in morphology, this being primarily associated with the electrical heterogeneity of seed surfaces. During crystallization, the space between the discrete particles was filled with the hydrothermal solution which represented a liquid interfacial layer exhibiting informative properties occurred under the influence of electrically active elements of the seed surface. At the boundary separating the liquid interfacial layers with particular informative properties from the rest of the solution volume, at early crystallization stages, together with the formation of discrete particles directly on the coated seed surface, growth of a continuous sodalite single crystal took place. The informative properties of seed surfaces, which are regularly modified due to coating with interfacial silver layers, determine the occurrence on local regions of seed surfaces (under appropriate crystallization conditions) of one or the other polymorphous modification: either hexagonalcancrinite, or cubicsodalite.M O P~H O~~ M o n n a m a u m : a1160 r e K c a r o H a n b H o f i -K a m p m w r a , an60 ~y 6 k i s e c~o B conanma.