Doctoral Dissertations

Keywords and Phrases

Dissolution behaviors; High performance liquid chromatography; Oxygen polarizability; Phosphate glasses; Raman spectroscopy; Structure

Abstract

The poor chemical durability remains a critical challenge for the application of phosphate glasses. This study investigates the compositional influences on the structure, properties and chemical durability of Li2O-ZnO-P2O5 glasses. Their structural characteristics were analyzed utilizing high-performance liquid chromatography, Raman spectroscopy, and X-ray photoelectron spectroscopy. The incorporation of (Li2O+ZnO) in LZeq glasses depolymerizes the phosphate network. In LZ40P and LZ45P glasses, Li+ initially replaces Zn2+ associated with non-bridging oxygens (NBOs) in Q2 tetrahedra. Once the substitution in Q2 is complete, further Li⁺ incorporation leads to the replacement of Zn2+ in Q1 tetrahedra.

For the LZeq glasses, these compositional and structural changes lead to an increase in glass density and refractive index, while decreasing the thermal stability against crystallization. Conversely, for the LZ40P glasses, the substitution of ZnO by Li2O leads to an increase in M-ONB and P-NBO bond lengths, a reduction in oxygen polarizability and optical basicity, which in turn lowers glass density, refractive index, and the thermal stability against crystallization. Notably, the preferential replacement of Zn2+ ions by two Li+ ions to charge-balance the Q2 units significantly influences the evolution of glass properties, with a distinct break in the property trends at 20 mol%. The chemical durability was evaluated in H2O and 0.1M HCl. The fastest dissolution rate was observed in 60Li2O·40P2O5 glass, while the slowest reaction rate observed in mixed Li/Zn compositions. The ion release mechanism suggests that phosphate network hydration and cation leaching significantly influence pH evolution.

Advisor(s)

Brow, Richard K.

Committee Member(s)

Kumar, Aditya
Lonergan, Charmayne E.
Ma, Hongyan
Fahrenholtz, William

Department(s)

Materials Science and Engineering

Degree Name

Ph. D. in Ceramic Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Summer 2025

Pagination

xiii, 134 pages

Note about bibliography

Includes_bibliographical_references_(pages 122-131)

Rights

© 2025 Han Zhang , All Rights Reserved

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 12528

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