Elastic properties of Na2O�?�ZnO�?�ZnF2�?�B2O3 oxyfluoride glasses

[摘要] Elastic properties of Na₂Oâ€�?�ZnOâ€�?�ZnF₂â€�?�B₂O₃ oxyfluoride glasses with different ZnF₂ concentrations have been investigated using ultrasonic velocity measurements at room temperature, at a frequency of 10 MHz. Glasses prepared by melt quenching method were suitably polished for the ultrasonic velocity measurements using pulse-echo superposition method. Various elastic moduli have been calculated and their compositional dependence has been examined. The compositional dependence of elastic moduli with the concentration of ZnF₂ shows decrease in the moduli initially, with further increase in ZnF₂ the moduli sharply increases and then again tend to decrease when ZnF₂ concentration is 20 mol%. The values of Poisson’s ratio lie in the range of 0.24â€�??0.30, which is typical to covalent bonded network. The variation of 𝜃_D with ZnF₂ indicates complex behaviour of the glass network. The results have been analysed in view of the modified borate glass network. Addition of ZnF₂ into the pure glass seems to influence the borate network by replacement of Bâ€�?�Oâ€�?�B linkages with Bâ€�?�Oâ€�?�Zn.

[学科分类] 材料工程

[关键词] Borate glasses;oxyfluoride glasses;elastic properties;dual role of Zn2+.