Physical, structural and elastic properties of Fe2O3-doped oxyfluoroborate glasses

Abstract

A series of Fe₂O₃-doped oxyfluoroborate 75B₂O₃–20NaF–5BaO glasses (Fe₂O₃ = 0, 2, 4, and 6 mol) were synthesized using the conventional melt-quenching method. The effect of Fe₂O₃ on the physical, structural, and elastic characteristics of synthesized glass samples has been studied. The non-crystalline characteristics of the prepared glass samples were validated through XRD analysis, while their structural properties were examined using FTIR spectroscopy. Elastic properties were investigated through the measurement of longitudinal and shear ultrasonic velocities, employing the pulse-echo technique. The observed density and computed molar volume were determined to be influenced by the content of Fe₂O₃. The ultrasonic velocities, elastic moduli, micro-hardness, and Debye temperature exhibited similar behavior across all glass compositions, showing an increase with increasing Fe₂O₃ content. The findings are analyzed concerning the alteration in the topology of the borate network. The incorporation of Fe₂O₃ led to the transformation of BO₃ structural groups into BO₄ structural groups, enhancing the network connectivity and increasing the rigidity of the glass structure and elastic moduli. A variety of compositional parameters, including the average separation between boron ions, mean atomic volume, glass packing density, dissociation energy per unit volume, and excess molar volume, were assessed in concerning Fe₂O₃ content. These parameters were then correlated with the elastic properties, drawing on established models and theories within the discipline. The theoretical elastic moduli, micro-hardness, and Poisson's ratio values were ultimately calculated and compared with the experimental ones.