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. 21, 1984
Filed:
Sep. 27, 1982
Joseph Nemeth, Harsens Island, MI (US);
Champion Spark Plug Company, Toledo, OH (US);
Abstract
A lead-free green ceramic body useful after firing as an electrical resistor, and a method for producing such a resistor, are disclosed. The method preferably comprises the steps of preparing a uniform, finely-divided mixture by blending, by weight, substantially 69 percent of a glass frit with substantially 8 percent of AlPO.sub.4, substantially 3 percent of conductive carbon and substantially 20 percent of a phenyl lower alkyl silicone resin which is curable to form a temporary binder for the conductive carbon and the glass frit. One preferred frit consists essentially of substantially 43 percent SiO.sub.2, 20 percent B.sub.2 O.sub.3, 21 percent Na.sub.2 O, 3 percent CaO, 8 percent BaO and 5 percent Li.sub.2 O. A shape is then pressed from the mixture; the shape is heated to 450-550 degrees F. for about 30 minutes and cooled to ambient temperature. Silver paint is then applied to the cooled shape and the painted shape is fired to vitrify the frit of the resistor. A lead-free carbon resistor according to the invention eliminates health hazards of human exposure to toxic lead compounds used in many resistors. A preferred resistor according to the invention also maintains an essentially constant resistance over time.