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:
Dec. 11, 1990
Filed:
Nov. 17, 1989
Kazuo Horinouchi, Niihama, JP;
Katsuya Maeda, Niihama, JP;
Sumitomo Chemical Company, Limited, Osaka, JP;
Abstract
Disclosed are zirconia ceramics superior in mechanical strength, hardness and toughness and a method for producing them. The zirconia ceramics contain ca. 7-12 mol % of cerium oxide and ca. 2-7 mol % of magnesium oxide and have an average crystal grain size of crystal grains thereof of 1 .mu.m or less, at least ca. 80 mol % of the crystal grains being tetragonal grains and the balance being monoclinic grains, and have a bending strength of at least 100 kg/mm.sup.2, a fracture toughness of at least 10 MNm.sup.-1.5 and a Vickers hardness of at least 1000 kg/mm.sup.2. The method comprises calcining a hydrate obtained by coprecipitation method from water-soluble salts of cerium and magnesium and a basic salt of zirconium or a hydrate obtained by adding water-soluble salts of cerium and magnesium to a zirconium hydrate and neutralizing the mixture of hydrates, further grinding the calcined hydrate to obtain zirconia powders of 1 .mu.m or less in average crystal grain size, then shaping the powders and sintering the resulting shaped product.