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. 21, 1989
Filed:
Oct. 09, 1987
Naochika Nunogaki, Kariya, JP;
Tetsuo Toyama, Anjo, JP;
Nobuei Ito, Okazaki, JP;
Kazuhiro Inoguchi, Okazaki, JP;
Nippondenso Co., Ltd., Kariya, JP;
Nippon Soken, Inc., Nishio, JP;
Abstract
An electrically insulating ceramic sintered body suitably used in a ceramic glow plug, for example, is formed by firing a mixed powder of 75 to 95 vol % of a basic material, 25 to 5 vol % of an additive and a sintering aid. The basic material is composed of at least one material selected from the group consisting of silicon nitride, aluminum nitride, and .beta.-sialon. The additive is composed of at least one material selected from the group consisting of silicide, carbide, nitride, and boride of metal, the additive having a thermal expansion coefficient larger than that of the basic material. And the sintering aid is composed of one of alumina in an amount of 3 to 50 wt % of the total amount of the basic material and the additive, and spinel in an amount of 2 to 15 wt % of the total amount of the basic material and the additive. The sintered body has the structure that particles of the additive cohere and the cohering additive particles are dispersed in particles of the basic material so as to be surrounded by the particles of the basic material and separated from adjacent cohering additive particles by the particles of the basic material. When the sintered body is used as a heater supporting member of the ceramic glow plug, the thermal expansion coefficient thereof can be controlled in accordance with that of the heater, and a high specific resistance of not less than 10.sup.5 .OMEGA. cm can be obtained.