Fabrication, Kinetics and Crystallography of Lithium Disilicate Glass-Ceramics
type: CreativeWork
description: This research project mainly focuses on three aspects of investigations on lithium disilicate glass-ceramics, namely, fabrication, kinetics, and crystallography. One of the objectives is to fabricate a high-strength glass-ceramic in complex lithium disilicate glass systems for dental restorative applications by means of compositional design of parent glass and heat treatment optimization. The second objective is to understand the nucleation mechanism and crystallization kinetics of lithium disilicate glasses by in situ and real-time observations of phase transition using X-ray diffraction (XRD) technique with the state-of-the-art synchrotron radiation. In the meantime, it is of interest to systematically study the evolution of crystallographic structure of the involved crystalline phases (mainly lithium metasilicate and/or disilicate), which is refined by Rietveld method from the as-received synchrotron XRD data, and discuss the relationship of phase transition and crystallographic evolution. Firstly, a lithium disilicate glass-ceramic, based on a well-documented SiO2–Li2O–Al2O3– P2O5–ZrO2 glass system, was developed. This glass ceramic has a three-point flexural strength of 307 MPa and Vickers hardness of 7.9–8.2 GPa. The glass-ceramic demonstrated a zigzag crack path, suggesting the fracture mechanism of crack deflection. The formation of cubic zirconia (c-ZrO2) with a spherical shape was identified (Chapter 4). Built on the experimental findings of Chapter 4, other new glass compositions (glasses B, C, E, and F) were designed, with MgO being a common additive. Glass-ceramics from glass B (Al2O3-free system) showed an optimized flexural strength of 439±93 MPa and Vickers indentation fracture (VIF) toughness of 0.93–1.29 MPa∙m1/2. Very limited amount of lithium metasilicate (LS) was detected by synchrotron radiation during glass crystallization. The investigation indicates that the crystallization temperature has a more profound effect than holding time on the phas…
abstract: This research project mainly focuses on three aspects of investigations on lithium disilicate glass-ceramics, namely, fabrication, kinetics, and crystallography. One of the objectives is to fabricate a high-strength glass-ceramic in complex lithium disilicate glass systems for dental restorative applications by means of compositional design of parent glass and heat treatment optimization. The second objective is to understand the nucleation mechanism and crystallization kinetics of lithium disilicate glasses by in situ and real-time observations of phase transition using X-ray diffraction (XRD) technique with the state-of-the-art synchrotron radiation. In the meantime, it is of interest to systematically study the evolution of crystallographic structure of the involved crystalline phases (mainly lithium metasilicate and/or disilicate), which is refined by Rietveld method from the as-received synchrotron XRD data, and discuss the relationship of phase transition and crystallographic evolution. Firstly, a lithium disilicate glass-ceramic, based on a well-documented SiO2–Li2O–Al2O3– P2O5–ZrO2 glass system, was developed. This glass ceramic has a three-point flexural strength of 307 MPa and Vickers hardness of 7.9–8.2 GPa. The glass-ceramic demonstrated a zigzag crack path, suggesting the fracture mechanism of crack deflection. The formation of cubic zirconia (c-ZrO2) with a spherical shape was identified (Chapter 4). Built on the experimental findings of Chapter 4, other new glass compositions (glasses B, C, E, and F) were designed, with MgO being a common additive. Glass-ceramics from glass B (Al2O3-free system) showed an optimized flexural strength of 439±93 MPa and Vickers indentation fracture (VIF) toughness of 0.93–1.29 MPa∙m1/2. Very limited amount of lithium metasilicate (LS) was detected by synchrotron radiation during glass crystallization. The investigation indicates that the crystallization temperature has a more profound effect than holding time on the phas…
author: Huang, Saifang
license: https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm
date published: 2015
date modified: 2026-07-24T01:03:18Z
provider: University of Auckland
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: ResearchSpace@Auckland

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property ID: Handle
value: https://hdl.handle.net/2292/26525