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. 23, 2013
Filed:
Mar. 14, 2008
Ryoji Toyoda, Niwa-gun, JP;
Yusuke Suzuki, Komaki, JP;
Yuki Hatano, Kasugai, JP;
NGK Spark Plug Co., Ltd., Aichi, JP;
Abstract
An insert includes a silicon nitride sintered body including β-SiNas a main component, Mg, and a rare-earth element Re (Y, La, Ce, Er, Dy, Yb). A content of Mg in terms of MgO is 1.0-7.0 mol %, a content of Re in terms of an oxide thereof is 0.4-1.0 mol %, and a total content of Mg and Re is from 1.7 to less than 7.5 mol %. The insert has a graded composition in which oxygen content increases from a surface of the sintered body toward an inside thereof such that 0.8-1.5 mass % of oxygen is contained in a region of less than 0.5 mm inside from the surface, 1.1-2.3 mass % of oxygen is contained in a region of 0.5 mm or more inside from the surface, and a difference in oxygen content between the regions is 0.1-1.0 mass %.