A study was made of the crystallization of five glass compositions of the pseudo-binary section beginning from the diopside composition to the akermanite composition. It was found that during crystallization of glasses from low temperatures the first phases which precipitate are metastable phases enriched with alkali-earth metal oxides. With increasing temperatures metastable phases irreversible transform into stable phases.It was shown theoretically that phenomena of such a kind can take place in complex glasses when the liquidus lines or liquidus surfaces of the phase diagram are flat. Crystallization of metastable phases is due to both thermodynamic and kinetic reasons.
展开▼
