Degree Type

Dissertation

Date of Award

1995

Degree Name

Doctor of Philosophy

Department

Materials Science and Engineering

First Advisor

Steve Warthen Martin

Abstract

The discovery of the fast ion conducting B[subscript]2S[subscript]3-based glasses has been one of the most significant development in the field of solid electrolytes. Considerable experimental studies have been done to maximize conductivities and chemical stabilities of these glass systems. Recently, the study of the structure and properties of these glasses compared to their oxide analog has become important;The IR spectra of M[subscript]2S + B[subscript]2S[subscript]3 (M = Li, K, Rb and Cs) and MS + B[subscript]2S[subscript]3 (M = Sr and Ba) thioborate glasses have shown the monotonic increase in tetrahedral boron units at the expense of thioboroxyl six-membered ring groups in a manner similar to that found in the alkali borate glasses in the low alkali glasses. Although the Li and K thioborate glasses were found to have structural similarities in the high alkali glasses, the Rb, Cs, Sr and Ba thioborate glasses have significant differences which arises from the fact that the alkali and alkaline earth ion plays a dominant role in controlling local structural environments;The density data and IR spectra for these glasses have shown the monotonic increase in tetrahedral boron units in the low alkali region, whereas the destruction of tetrahedral boron units arising from the formation of trigonal boron units with terminal non-bridging sulfurs for the high alkali glasses. In contrast to this behavior, the Tg measurements have shown the decreasing Tg with the addition of alkali modifier in the alkali thioborate glasses in the low alkali region. It is apparent that, although the SRO are similar in both systems, there are significant differences in the IRO and we have proposed that sulfur ions plays a dominant role in degrading IRO structure rather than enhancing.

DOI

https://doi.org/10.31274/rtd-180813-11338

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Jaephil Cho

Language

en

Proquest ID

AAI9531726

File Format

application/pdf

File Size

194 pages

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