Effect of TeO2 on the elastic moduli of sodium borate glasses

• Published in: Physica. B, Condensed matter Vol. 348; no. 1-4; pp. 475 - 484
• Main Authors: SADDEEK, Yasser B, LAMIA ABD EL LATIF
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 01.05.2004
• Subjects: Condensed matter: structure, mechanical and thermal properties; Elasticity, elastic constants; Exact sciences and technology; Fatigue, brittleness, fracture, and cracks; Lattice dynamics; Mechanical and acoustical properties of condensed matter; Mechanical properties of solids; Physics; Elastic modulus; Transducers; Shear; Molar volume; Ultrasonic waves; 62.20.Dc Sodium borate glasses; 43.25.dc; Lattice vibrations; Packing density; Density; 61.43.Fs; Sound velocity; Quenching; Debye temperature; Borate glasses; Ring diameter; Sodium; Poisson ratio; Vibrational modes; Elastic properties; Borates; Strain rate
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2004.02.001

Sodium borate glass containing tellurite as TexNa2-2xB4-4xO7-5x with x = 0, 0.05, 0.15, 0.25 and 0.35 have been prepared by rapid quenching. Ultrasonic velocity (both longitudinal and shear) measurements have been made using a transducer operated at the fundamental frequency of 4 MHz at room temperature. The density was measured by the conventional Archimedes method. The elastic moduli, the Debye temperature, Poisson's ratio, and the parameters derived from the Makishima-Mackenzie model and the bond compression model have been obtained as a function of TeO, content. The monotonic decrease in the velocities and the elastic moduli, and the increase in the ring diameter and the ratio Kbc/Ke as a function of TeO2 modifier content reveals the loose packing structure, which is attributed to the increase in the molar volume and the reduction in the vibrations of the borate lattice. The observed results confirm that the addition of TeO, changes the rigid character of Na2B4O7 to a matrix of ionic behaviour bonds (NBOs). This is due to the creation of more and more discontinuities and defects in the glasses, thus breaking down the borax structure.