Structure and properties of low-silica calcium aluminosilicate glasses

The structure of three calcium aluminosilicate glasses with low-silica content (61CaO · 39Al2O3 (Ca0.39), 55CaO · 35Al2O3 · 10SiO2 (Ca10.35) and 49CaO · 31Al2O3 · 20SiO2 (Ca20.31)), synthesized by a standard quenching technique, were studied by X-ray and neutron diffraction. The data are consistent with the hypothesis that Si and Al are present in tetrahedral sites and Ca in octahedral sites for all compositions. Si–T (T=Si or Al) and Si–O2 contributions (where O2 means the second nearest oxygen) appear at 10 mol% silica content, which indicate that silicon enters the aluminate network.