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
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-08 17:37
CPC Classifications
C; C03; C03C; C03C10/00; C03C10/0054
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
55 words
A glass-ceramic composition consisting of, in its original melt and on a weight basis, about 57 parts SiO 2 , about 21 parts ZrO 2 , about 5 parts Li 2 O, and about 17 part B 2 O 3 ; wherein the ZrO 2 in the finished glass-ceramic is present in metastable tetragonal form.
Claim 2
Dependent Claim
55 words
A glass-ceramic composition consisting of, in its original melt and on a weight basis, about 57 parts SiO 2 , about 21 parts ZrO 2 , about 5 parts Li 2 O, and about 17 part B 2 O 3 ; wherein the ZrO 2 in the finished glass-ceramic is present in metastable tetragonal form.
Claim 3
Dependent Claim
64 words
A glass-ceramic composition consisting of, in its original melt and on a weight basis, about 57 parts SiO 2 , about 21 parts ZrO 2 , about 5 parts Li 2 O, about 17 parts B 2 O 3 , and about 0.5 parts Y 2 O 3 ; wherein the ZrO 2 in the finished glass-ceramic is present in a metastable tetragonal form.
Claim 4
Dependent Claim
64 words
A glass-ceramic composition consisting of, in its original melt and on a weight basis, about 57 parts SiO 2 , about 21 parts ZrO 2 , about 5 parts Li 2 O, about 17 parts B 2 O 3 , and about 0.5 parts Y 2 O 3 ; wherein the ZrO 2 in the finished glass-ceramic is present in a metastable tetragonal form.