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:
Apr. 01, 1986
Filed:
Sep. 29, 1983
Juris Verzemnieks, Tacoma, WA (US);
The Boeing Company, Seattle, WA (US);
Abstract
A method for producing .alpha.-silicon nitride whiskers. Silicon is blended with amorphous silicon nitride and a pore-forming composition particles able to be removed without leaving a residue, such as naphthalene particles. The mixture is compacted to a desired shape, after which the pore-forming particles are removed from the mixture to form a porous silicon precursor compact having the desired shape. The silicon precursor is reacted with a substance that releases free nitrogen, such as nitrogen or dry ammonia. The reaction is carried out at a temperature sufficiently high to form an identically shaped porous compact of .alpha.-silicon nitride whiskers but sufficiently low to avoid subliming substantially all of the formed whiskers. Preferably, the reaction is carried out in a range between about 1100.degree. C. and 1500.degree. C. The shaped porous compact of .alpha.-silicon nitride whiskers may be impregnated with a resin binder, a liquid metal, a colloidal suspension, an ionic solution or a gaseous material to form a composite. Alternatively, the compact of .alpha.-silicon nitride whiskers formed by the method described above may be broken down by crushing or grinding to form individual whiskers.