Quantitative Analysis and Prediction of Elastic Properties of Tungstate–Tellurite Glasses Doped with Bi2O3

Abstract

In this work, the elastic properties of two tellurite glass series 80TeO₂-(20−x)WO₃-xBi₂O₃ (80TeWBi) and 70TeO₂-(30−x)WO₃-xBi₂O₃ (70TeWBi) (where x = 0 mol.%, 5 mol.%, and 10 mol.%) were quantitatively analyzed and predicted. Many structural and compositional parameters, including the density of network bonds, mean cross-link density, average bond-stretching force constant, total packing density, and dissociation energy per unit volume, were calculated using bond compression (BC), ring deformation (RD), and Makishima–Mackenzie (M–M) models. These parameters were correlated with experimental elastic properties to explore the structural role of WO₃ and Bi₂O₃ in the tellurite network. It was found that WO₃ enters the tellurite network of Bi₂O₃-free 80TeO₂-20WO₃ and 70TeO₂-30WO₃ glasses as a network former. This stiffened the structure through the formation of WO₄ tetrahedral units, WO₆ octahedral units, and Te–O–W linkages. As a result, the theoretical bulk modules (K_bc) increased from 73.23 GPa to 83.90 GPa whereas the theoretical Poisson's ratio decreased from 0.235 to 0.225 with increasing WO₃ mol.%. Meanwhile, Bi₂O₃ enters the network of TeO₂-WO₃-Bi₂O₃ glasses as a network modifier. This weakens the glass structure and results in the transformation of some TeO₄ trigonal bipyramids into TeO₃ trigonal pyramids by breaking the Te–O–W linkages and creating non-bridging oxygen atoms. Excellent agreement was achieved between the theoretical and experimental values of elastic moduli and Poisson's ratio.