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:
Jun. 25, 1985
Filed:
Jun. 12, 1984
Nils Claussen, Leonberg, DE;
Manfred Ruhle, Ditzingen, DE;
Gunter Petzow, Leinfelden-Echterdingen, DE;
Max-Planck-Gesellschaft zur Forderung der Wissenschaften, Gottingen, DE;
Abstract
A ceramic body of zirconium dioxide containing, if desired, aluminum oxide, and partially stabilized with yttrium oxide and/or one or more rare earth oxides (e.g., cerium dioxide) and/or magnesium oxide and/or calcium oxide is partially stabilized with 0.5 to 5 mole-% of yttrium oxide and/or 5 to 12 mole-% of magnesium oxide and/or calcium oxide and/or cerium dioxide or one or more rare earth oxides, is 30 to 100% in the tetragonal lattice modification and has in the surface region a content of yttrium oxide, cerium dioxide, magnesium oxide, calcium oxide or rare earth oxide that is 1 to 20 mole-% higher than the average content, such that the body is coated with a thin, PSZ-like layer in a more highly stabilized tetragonal or with a layer that is predominantly in the cubic lattice form. For preparation, the surface of an already sintered or only presolidified compact of partially stabilized zirconium oxide is brought into intimate contact with yttrium oxide, cerium dioxide, magnesium oxide, calcium oxide and/or another rare earth powder or a zirconium dioxide powder containing at least 12 mole-% of yttrium oxide and/or other stabilizer oxides, and then annealed at 1000.degree. to 1600.degree. C. until a more highly stabilized tetragonal or predominantly cubic surface layer of 0.1 to 200 micrometers thickness and 2 to 20 mole-% higher content of yttrium oxide, cerium dioxide, magnesium oxide, calcium oxide or rare earth oxide has formed.