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:
Jul. 02, 1991
Filed:
Oct. 27, 1989
Francis H Dulin, Rochester Hills, MI (US);
Champion Spark Plug Company, Toledo, OH (US);
Abstract
A semi-conducting ceramic is disclosed. The ceramic consists essentially of from 50 percent to 72 percent of silicon carbide particles, from 25 percent to 47 percent of silicon nitride particles and a modified silicon oxynitride glass bonded to the silicon carbide particles and bonding the silicon nitride particles together. An improvement in a method for producing an article which comprises silicon carbide particles dispersed in a matrix is also disclosed. The method includes the step of firing or sintering the article to convert the matrix to a densified ceramic with the formation of a liquid phase. The improvement involves embedding the article, prior to firing, in a cover material which contains powdered silicon and maintaining a nitrogen or an inert atmosphere in contact with the cover material during firing. The amount of silicon in the cover material and the composition of the atmosphere are such that the silicon carbide particles are protected against oxidation.