Formation of clathrate hydrates under crystallization of gas-saturated amorphous ice

摘要

Layers of methane-saturated amorphous ice were obtained by deposition of molecular beams of water and gas on a substrate cooled with liquid nitrogen. Their heating is accompanied by glass transition (softening) and subsequent spontaneous crystallization. The avalanche-type initiation of crystallization centers captures the gas molecules and does not lead to their displacement by the motion of the crystallization front. Under crystallization of amorphous water-gas condensates in conditions of deep metastability the formation of gas hydrates takes place. Class-transition and crystallization temperatures of the condensates were determined by changes in their dielectric properties under heating. The method of differential thermal analysis has been used to investigate the kinetics of crystallization of amorphous water layers. Properties that characterize the water crystallization kinetics have been determined on the basis of the obtained data on the dependence of the crystallization temperature on the heating rate.