Instrumentation for in situ observation of growth and dissolution processes of crystals in high temperature solutions at 1600°C

Abstract

An instrument for in situ observation of growth and dissolution processes of silicate crystals at elevated temperatures up to 1600°C has been newly designed. This instrument consists of a growth cell with a specially designed liquid holder, a digital temperature controller using a highly stabilized DC power unit, an optical microscopic system for in situ observation of the processes with transmitted light and a high resolution TV system for recording and displaying optical images. The stability of the temperature around the growing crystal has been improved to satisfy ±0.3°C at 1600°C in a high temperature solution of small volume (≅0.06 cm³).
This combination makes it possible to carry out the direct observations not only of growth and dissolution processes of crystals in liquid phases at high temperatures with clarity, but also of the diffusion layers and convection around growing or dissolving crystals. This system has been successfully applied to the diopside-forsterite-silica system.