Glass ceramic toughened with tetragonal zirconia
Abstract
Abstract 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. Nucleating 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° C. and is then heat-treated at a temperature within the range of 800° to 1200° C. in order to precipitate tetragonal ZrO 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.
Inventors
- 👤 Keith D. Keefer
- 👤 Terry A. Michalske
Bibliographic Details
Claims Analysis
Total Claims: 4References Cited (Backward Citations)
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