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. 01, 1992
Filed:
Jan. 15, 1992
Sophia R Su, Weston, MA (US);
GTE Laboratories Incorporated, Waltham, MA (US);
Abstract
A method of making fully dense, crack-free silicon nitride articles using polysilanes as a binder. Polysilane is dissolved in a solvent and a silicon nitride composition including a densification aid is added to form a homogeneous mixture. The mixture is dried to form a powder, and molded at a temperature less than 100.degree. C. to form a molded article. Alternatively, the slurry is poured into a mold and vacuum filtered to form a cake, then isostatically pressed at a temperature of approximately 90.degree. C. The molded article or pressed cake is heated at a rate of approximately 5.degree. C./min to about 900.degree. C. in a nonoxidizing atmosphere and held at about 900.degree. C. for a time sufficient to decompose the polysilane. The article is sintered in a nonoxidizing atmosphere at a temperature of about 1685.degree.-1900.degree. C. to form a silicon nitride article free of cracks and having a density greater than 3.5 g/cc.