This work presents the results of modeling the three-component Li2O-K2O-SiO2 oxide system during cooling from 1250 °C under two different conditions. Calculations were performed for the content of structural units formed during glass formation and for the structure of substances resulting from crystallization of a multialkali silicate melt containing equal amounts of lithium and potassium. The structure was predicted using thermodynamic modeling approaches for glasses and first-principles calculations for crystalline samples. The results of glass structure modeling for compositions 16.5Li2O-16.5K2O-67SiO2, 20Li2O-20K2O-60SiO2 and 25Li2O-25K2O-50SiO2 were shown to be consistent with Raman spectroscopy data. The crystalline phases in annealed samples of the same compositions were identified using X-ray diffraction (XRD), while the possible coexistence regions of stable phases in this system were evaluated using DFT calculations. A good qualitative agreement was demonstrated between the experimental results and theoretical calculations to confirm the crystallization of SiO2, KLiSi2O5, Li2SiO3, K2SiO3 and KLi3SiO4 phases in the system. The results of this work validated the selected computational approaches for modeling glass formation and crystallization of the oxide multialkali melt.
Koroleva et al. (Fri,) studied this question.