Enhancing glass-forming ability and mechanical properties of barium-calcium-aluminate glasses through ZnO inclusion

Calcium aluminate (CA) glasses have garnered attention in the field of infrared photonics due to their low phonon energy. Nonetheless, the poor glass-forming ability (GFA) and strong crystallization tendency have hindered their utilization in various technological applications. Therefore, we demonstrate here that the substitution of ZnO for CaO enhances the GFA of 29Al2O3–(66X)CaO–5BaO–(X)ZnO (X = 0,7,10,15,20,25) glasses and improves their mechanical properties. The structural characterization using Raman, 27Al MAS-NMR spectroscopy and MD simulations reveal that, Zn2+ ions adopt tetrahedral coordination and contribute as network formers along with Al3+ ions. Notably, MD simulations indicate a preference of ZnO4 units for the CaO6 sites to convert non-bridging oxygens to bridging oxygens. The decrease in glass transition temperature and the increase in elastic modulus is noticed which correlated with the structural changes in the studied glasses. These findings provide valuable insights into the design and development of stable multicomponent CA glasses for photonic applications.