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:
Mar. 22, 1983
Filed:
Dec. 21, 1981
John A Mangels, Flat Rock, MI (US);
John R Baer, Ypsilanti, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
A method is disclosed in this specification for forming a densified silicon nitride article. The method is initiated by forming a reaction bonded article of moderate density. This moderate density reaction bonded article has a primary phase of substantially pure grains of silicon nitride surrounded by a secondary grain boundary phase. The secondary grain boundary phase contains silicon nitride, silicon dioxide and a densification aid incorporated in the reaction bonded article of moderate density. The compounds forming the secondary grain boundary phase are present either in their pure forms or interacted with one another. The reaction bonded article is packed in a packing powder which contains portions of the pure compounds found in or interacted with one another to define the secondary grain boundary phase. The reaction bonded article of moderate density is heated in the packing powder to a temperature and for a time whereby interaction of the secondary grain boundary phase and the packing powder may take place. The interaction takes place so that a new grain boundary phase can be developed about the substantially pure grains of silicon nitride. The new grain boundary phase developed is a unitary phase of a selected composition.