Evaporation rate anisotropyof forsterite

Abstract

Evaporation anisotropy of a synthetic single crystal of forsterite was investigated by high temperature vacuum experiments at temperatures from 1500 °C to 1750 °C. Anisotropy of evaporation rate is significant at temperatures below 1730 °C, where the rate is largest on (001), intermediate on (100), and smallest on (010) surfaces. The activation energies are 641, 592, and 570kJ/mole for (100), (010), and (001) surfaces, respectively. The anisotropy of evaporation rate is negligible at temperature above 1740 °C, where a different type of evaporation pits appears with a high density on the (010) surface.