The influence of Bi 2O 3 on yLi2O · (1 − y){ xBi2O3(1 − x) B2O3} glass system

Abstract

The thermal, electrical and structural characterization of yLi 2 O · (1 − y)/ xBi 2 O 3 · (1 − x) B 2 O 3 ( y = 0.4, 0.5) glass system has been investigated. The decrease in T g with the increase in Bi 2O 3 content has been attributed to the increasing number of non-bridging oxygen atoms from BO bonds and also the BiO linkage which is relatively weaker. The conductivity vs. Bi 2O 3 composition curve exhibits two maxima at Bi 2 O 3 content = 0.2 mol% and 0.6 mol% for y = 0.5 compositions. This is interpreted in terms of the mixed-former effect and modification effect of Bi 2O 3 on this glass system, respectively. For glasses with y = 0.4, conductivity has been slightly enhanced at Bi 2 O 3 content = 0.2 mol% which is due to the mixed-former effect. Results obtained from the XPS studies have shown: 1) for samples with y = 0.5, the number of non-bridging oxygen atoms from BO bond increases with the increase in Bi 2O 3 content for composition range 0.2 mol% < Bi 2 O 3 content ≤ 0.8 mol% and gets to a maximum value at Bi 2 O 3 content = 0.6 mol% where the conductivity has also exhibited a maximum value. For higher Bi 2 O 3 content ( ≥ 1 mol%), O ls spectra of Bi-O-Bi and Bi-O-B bonds ( O ls(3)) have been separated out. When Bi 2 O 3 content = 20 mol%, O ls spectrum of Bi-O − ( O ls(4)) has been separated out. 2) for samples with y = 0.4, O 1 s(3) could be separated out for Bi 2 O 3 content ≥ 0.6 mol%. It is obvious that in 0.4 Li 2 O · 0.6( xBi 2 O 3 · (1 − x) B 2 O 3) system more Li + ions associate with Bi 2O 3 and in O.5 Li 2 O · 0.5{ itxBi 2O 3(1 − x)B 2O 3} system they prefer borate units.