Glass ceramic toughened with tetragonal zirconia
A phase transformation-toughened glass ceramic and a process for making it are disclosed. A mixture of particulate network-forming oxide, network-modifying oxide, and zirconium oxide is heated to yield a homogeneous melt, and this melt is then heat treated to precipitate an appreciable quantity of tetragonal zirconia, which is retained at ambient temperature to form a phase transformation-toughened glass ceramic. Nuclearing agents and stabilizing agents may be added to the mixture to facilitate processing and improve the ceramic's properties. Preferably, the mixture is first melted at a temperature from 1200 to 1700/sup 0/C and is then heat-treated at a temperature within the range of 800 to 1200/sup 0/C in order to precipitate tetragonal ZrO/sub 2/. The composition, as well as the length and temperature of the heat treatment, must be carefully controlled to prevent solution of the precipitated tetragonal zirconia and subsequent conversion to the monoclinic phase.
- DOE Contract Number:
- AC04-76DP00789
- Assignee:
- Dept. of Energy
- Application Number:
- ON: TI85005776
- OSTI ID:
- 6368052
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CERAMICS
PRECIPITATION HARDENING
GLASS
ZIRCONIUM OXIDES
HEAT TREATMENTS
TETRAGONAL LATTICES
CHALCOGENIDES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
HARDENING
OXIDES
OXYGEN COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
ZIRCONIUM COMPOUNDS
360201* - Ceramics
Cermets
& Refractories- Preparation & Fabrication