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:
Nov. 25, 1980
Filed:
Jul. 02, 1979
John A Mangels, Flat Rock, MI (US);
Ford Motor Company, Dearborn, MI (US);
Abstract
A method of manufacturing silicon nitride particles, either in an aglomerated or unaglomerated form, is disclosed. Basically, the particles to be nitrided are placed in an enclosed furnace and heated to a suitable temperature at which the enclosed furnace is filled with an initial gaseous mixture of nitrogen and hydrogen, the mixture containing not more than about 6% by volume hydrogen. Thereafter, the material is heated in the enclosed furnace to a temperature of about 900.degree. C. to about 1000.degree. C. at which time the nitrogen starts to react with the silicon in the furnace. Thereafter, the enclosed furnace is demand filled with a nitriding gas mixture consisting essentially of 1 to 10% by volume helium and about 99 to 90% by volume nitrogen. The furnace is heated to a suitable nitriding temperature and the demand filling of the chamber with the nitriding gas helium/nitrogen combination is continued until the nitriding operation is terminated. The enclosed furnace is then cooled to room temperature and the nitrided silicon material recovered. The use of helium in the nitriding gas obtained all of the benefits one obtains when nitriding gas is a combination of hydrogen and nitrogen, but does not produce an explosive mixture.