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:
Feb. 24, 2004
Filed:
Apr. 10, 2001
Applicant:
Inventors:
Tomonori Niwa, Ichinomiya, JP;
Tetsuji Yogo, Aichi, JP;
Assignee:
NGK Spark Plug Co., Ltd., , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C04B 3/548 ;
U.S. Cl.
CPC ...
C04B 3/548 ;
Abstract
A zirconia containing ceramic ball is formed of a zirconia containing ceramic material which contains in an amount of not less than 10% by volume the zirconia ceramic phase composed predominantly of zirconium oxide. The size of the largest pore among pores present in a region extending radially from the surface of the ball to a depth of 50 &mgr;m as observed on a polished cross section of the ball taken substantially across the center of the ball is not greater than 3 &mgr;m. The ceramic ball can be manufactured through firing a green body whose relative density is enhanced to not lower than 61% by use of rolling granulation.