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:
Oct. 02, 1990
Filed:
Nov. 21, 1988
Takamitsu Eonomoto, Ube, JP;
Hiroshi Ueda, Ube, JP;
Midori Kawahara, Ube, JP;
Naoki Okada, Ube, JP;
Noboru Murata, Ube, JP;
Central Glass Company, Limited, Ube City, JP;
Abstract
A modified lead barium titanate ceramic which has a fundamental composition of (Ba.sub.1-x-y Sb.sub.y Pb.sub.x)TiO.sub.3, where x is not greater than 0.9 and usually not smaller than 0.6 and y is from 0.001 to 0.1, and has a high positive temperature coefficient of resistivity (PTCR) over a range of temperature higher than about 350.degree. C. at the lower boundary, is produced by using a metal salt of an organic acid such as lead titanate salt of oxalic acid as the source of Pb and by adding at least one of BaCO.sub.3, SiO.sub.2, BN and TiO.sub.2 to the raw materials of the above fundamental composition. After thermally decomposing the organic acid metal salt the mixture of the raw materials including the additive(s) is compacted and sintered. By this method the sintering is achieved with good reproducibility and with little dissipation of lead, and the obtained titanate ceramic is good and durable in the PTCR characteristics and hence is useful as the material of a PTC thermistor functioning at medium-to-high temperatures.