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:
Oct. 22, 1991
Filed:
Feb. 16, 1990
Marcellus Peuckert, Hofheim am Taunus, DE;
Cornelia Boberski, Hofheim am Taunus, DE;
Hoechst Aktiengesellschaft, Frankfurt am Main, DE;
Abstract
A multi-phase ceramic which is resistant to high temperatures and contains 25-85 % by weight of crystalline .beta.-silicon nitride, 11 to 70% by weight of crystalline cubic HfO.sub.2 and an amorphous glass phase which, in addition to silicon, contains at least one of the elements magnesium, yttrium and/or the rare earths and if appropriate aluminum, has good mechanical properties. To prepare the ceramic, a mixture of 25-85% by weight of pulverulent a-silicon nitride, 11 to 70% by weight of monoclinic HfO.sub.2 and 5-20% by weight of at last one oxide of the elements magnesium, yttrium and/or the rare earths (from Sm to Yb) is shaped to a body and this is sintered to give a dense body at 1,700-2,000.degree. C.