Abstract:
Low-temperature crystallization of amorphous materials has been analyzed theoretically taking into account nonstationary nucleation. The kinetics of crystallization of amorphous water layers, formed by depositing molecular beams on a substrate cooled by liquid nitrogen, has been investigated by differential thermal analysis. The conditions of gas hydrate formation in low-temperature amorphousice layers saturated with carbon dioxide have been studied. The glass-transition and crystallization temperatures of the gas hydrates have been determined from the change in dielectric properties upon heating. Under the deep-metastability conditions, crystallization of water–gas layers leads to the formation of crystallohydrates. Gas molecules are captured by the avalanche-like nucleation of crystallization centers and, therefore, are not displaced by the moving crystal–melt interface. Gas-hydrate samples formed in nonequilibrium water–gas layers are convenient for studying their thermophysical properties.
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