Ceramic body of zirconium dioxide (ZrO.sub.2) and method for its preparation

USRE32449E · kind E · reissue

Assignee

• Max-Planck-Gesellschaft zur Föderung der Wissenschaften e.V. · US

Inventors

• Nils Claussen · Schwäbisch Hall, DE
• Manfred Ruhle · Ditzingen, DE
• Gunter Petzow · Echterdingen, DE

Key dates

• Filing date: Jan 23, 1986
• Grant date: Jun 30, 1987
• Expiry date: Jan 23, 2006

Classification

• Technology area (CPC —): General

Abstract

A ceramic body of zirconium dioxide containing, if desired, aluminum oxide, nd 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 1…