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:
Aug. 14, 2012
Filed:
Oct. 22, 2010
Jun Sugawara, Fukuoka, JP;
Jun Sugawara, Fukuoka, JP;
Krosakiharima Corporation, Fukuoka, JP;
Abstract
The present invention is intended to drastically improve a precision polishing characteristic of a cordierite-based sintered body which has low thermal expansibility, high dimensional long-term stability and high rigidity (high elastic modulus). The cordierite-based sintered body comprises cordierite as primary components, and one or more selected from the group consisting of La, Ce, Sm, Gd, Dy, Er, Yb and Y in an oxide-equivalent amount of 1 to 8 mass %, without any crystal phase other than a cordierite crystal phase. A mass ratio of primary components of the cordierite satisfies the following relations: 3.85≦SiO/MgO≦4.60, and 2.50≦AlO/MgO≦2.70, and the cordierite-based sintered body after being subjected to precision polishing has a precisely polished surface with an average surface roughness (Ra) of 1 nm or less.