Multicomponent oxide glasses are important in many scientific fields and for technological applications: for geo-chemistry and earth science, industrial glass production, metallurgy and novel low CO₂ building materials. The aim of this work is to investigate the structural and physico-chemical properties of selected glasses in the (Ca_1-xMg_x)O-Al₂O₃ system. This system is important from both a fundamental and an applied point of view.
The work includes a comprehensive experimental study and theoretical classical molecular dynamics simulations. Five glass samples were chosen for the investigation: C_12-nM_nA₇, where n=0..4, C – CaO, M – MgO, A – Al₂O₃. The synthesis of glasses was conducted by the classical quenching method using a platinum/gold crucible in air.
The structural properties of the glasses were determined by Raman and XANES spectroscopy. The density of solid glasses was measured using the Archimedes method, by immersion in toluene. The decrease of the glass transition temperature with increasing MgO content in the multicomponent glass was obtained by differential scanning calorimetry (DSC). The thermodynamic properties were measured by two techniques. The specific heat capacity of the studied glasses was measured by high-precise Calvet Pro DSC from room temperature to 800 K. High-temperature drop-solution calorimetry was used to determine the enthalpy of formation from the constituent oxides at 298.15 K of the studied glasses. In addition to the experimental part of the work, classical molecular dynamics simulations (MD) were conducted for the all glass compositions. New pair interaction parameters for pure MgO were merged with literature data for the CaO-Al₂O₃ binary system, and the calculated properties obtained by MD were compared with the experimental values.
The work was financially supported by Russian Ministry of Science and Education, grant No. 075-15-2021-1353.