The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 12, 1977
Filed:
Sep. 04, 1975
Herbert L Johns, Madison, OH (US);
Corning Glass Works, Corning, NY (US);
Abstract
Mature zirconia ceramic compositions stabilized in the monoclinic and tetragonal structure with 0.1-5% ZnO and as little as 0.5% of a primary stabilizer selected from MgO, Y.sub.2 O.sub.3 or combinations thereof. Compacted ceramic compositions are fired and matured at temperatures below the volatilization point of ZnO and in the range of 2750.degree.-2950.degree. F. Zirconia is conventionally batched with magnesia, yttria or mixtures thereof, with or without other known stabilizers including ceria and calcia, together with up to about 5% ZnO and then compacted and sintered at a temperature which retains at least 0.1% ZnO in the fired body. Conventional cooling is prescribed. Subsequent thermal cycling of the fired body between 400.degree. and 2500.degree. F. reveals a stable body with no degradation in strength. Magnesia stabilized compositions show no signs of early destabilization on thermal cycling and may even show increasing room temperature strength as cycling progresses.