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:
Dec. 14, 1976
Filed:
Jul. 30, 1974
Nobuei Shimojo, Ichikawa, J;
Ichihito Minesaki, Yokohama, J;
TDK Electronics Company, Limited, Tokyo, J;
Abstract
A method of manufacturing barium titanate semiconducting ceramics having a positive temperature coefficient characteristic of resistivity in which a composite, expressed by a general formula (Ba.sub.1.sub.-x.sub.-y Pb.sub.x R.sub.y) TiO.sub.3 (where 0<x.ltoreq.0.8, y is the remainder and R represents a rare earth element) is mixed with either tantalum or niobium or both in the amount of 0.05 to 0.5 atomic % and fired in the air or in an atmosphere containing oxygen, the total amount of the rare earth in the composite combined with the total amount of tantalum or niobium or both added thereto being in the range of 0.1 to 0.55 atomic %. The addition of tantalum and/or niobium in this manufacturing method prevents the evaporation of lead from the composite and eliminates the need to employ a lead oxide gas atmosphere while providing semiconducting ceramics having stable and excellent ceramic and electrical characteristics.