Comparison of the effects of titania and tantalum oxide nucleating agents on the crystallization of Li sub 2 O sm bullet Al sub 2 O sub 3 sm bullet 6SiO sub 2 glasses

Journal Article · Fri Dec 01 00:00:00 EST 1989 · Journal of the American Ceramic Society; (USA)

DOI:https://doi.org/10.1111/j.1151-2916.1989.tb06085.x· OSTI ID:6785797

Hsu, J Y; Speyer, R F ^[1]

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1. Alfred Univ., NY (USA)

This paper reports the crystallization mechanism in Li{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2} (1:1:6) glasses investigated with TiO{sub 2} or Ta{sub 2}O{sub 5} as nucleation agents, by differential thermal analysis, x-ray diffractometry, and transmission electron microscopy. Phase separation occurred prior to crystallization in all of the glasses studied. Both TiO{sub 2} and Ta{sub 2}O{sub 5} additives promoted nucleation and crystal growth in the bulk glasses by causing the precipitation of crystalline precursor phases dispersed within phase-separated glass, which acted as heterogeneous nucleation sites for {beta}-quarts ({ital ss}) (solid solution) formation. Upon reheating glasses with Ta{sub 2}O{sub 5} s the nucleating agent, phase separation occurred, followed by LiTa{sub 3}O{sub 8} and Ta{sub 2}O{sub 5} nucleation and limited growth as the first-formed crystalline phases, and then crystallization of {beta}-quartz structured solid solution, which nucleated and grew from the LiTa{sub 3}O{sub 8}/Ta{sub 2}O{sub 5} crystallites.

• OSTI ID: 6785797
• Journal Information: Journal of the American Ceramic Society; (USA), Vol. 72:12; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALUMINIUM OXIDES
DIFFERENTIAL THERMAL ANALYSIS
LITHIUM OXIDES
SILICON OXIDES
CRYSTALLIZATION
PHASE STUDIES
SOLID SOLUTIONS
TANTALUM OXIDES
TITANIUM OXIDES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
ALUMINIUM COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
DIFFRACTION
DISPERSIONS
ELECTRON MICROSCOPY
LITHIUM COMPOUNDS
MICROSCOPY
MIXTURES
OXIDES
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
REFRACTORY METAL COMPOUNDS
SCATTERING
SILICON COMPOUNDS
SOLUTIONS
TANTALUM COMPOUNDS
THERMAL ANALYSIS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies
400101 - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures
360201 - Ceramics
Cermets
& Refractories- Preparation & Fabrication