Electrical resistor material, resistor made therefrom and method of making the same
AssigneeTRW Inc.
InventorsRichard L. Wahlers, Kenneth M. Merz
Life of this patent
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Abstract
A vitreous enamel resistor material comprising a mixture of a vitreous glass frit and fine particles of tin oxide (SnO.sub.2). An electrical resistor is made from the resistor material by applying the material to a substrate and firing the coated substrate to a temperature at which the glass melts. The tin oxide is preferably heat treated prior to mixing with the glass frit. Upon cooling, the substrate has on the surface thereof, a film of the glass having the particles of the tin oxide embedded therein and dispersed therethroughout. The resistor material provides a resistor having a wide range of resistivity and a low temperature coefficient of resistance.
Claims21
A vitreous enamel resistor material adapted to be applied to and fired on a substrate to form an electrical resistor with a relatively low temperature coefficient of resistance consisting essentially of a mixture of tin oxide particles and a glass frit, said glass frit having a softening point below the melting point of the tin oxide particles, said mixture being fired in an inert atmosphere to a temperature between approximately 850.degree. C. and 1150.degree. C., said tin oxide being present in the amount of 20% to 70% by volume.
A method of making electrical resistors providing selected resistivities within a wide range and with controlled temperature coefficients of resistance comprising the steps of
- mixing together in selected amounts a glass frit and conductive particles consisting essentially of tin oxide, the glass frit being present in the amount of 30% to 80% by volume,
- applying said mixture to a surface of a substrate,
- firing said coated substrate in an inert atmosphere to a selected temperature between approximately 850.degree. C. and 1150.degree. C. at which the glass softens but below the point at which the tin oxide melts, and
- cooling the coated substrate to form a layer of glass bonded to the substrate and having conductive particles of tin oxide embedded in and dispersed throughout the glass.
An electrical resistor of the vitreous enamel type characterized by having a resistivity within a wide range and a relatively low temperature coefficient of resistance made by
- mixing together in selected amounts a glass frit and conductive particles consisting essentially of tin oxide, the glass frit being present in the amount of 30% to 80% by volume,
- applying said mixture to a surface of a substrate,
- firing said coated substrate in an inert atmosphere to a temperature between approximately 850.degree. C. and 1150.degree. C. at which the glass softens and below the point at which the tin oxide melts, and
- cooling the coated substrate to form a resistive layer of glass bonded to the substrate and having conductive particles of tin oxide embedded in and dispersed throughout the glass.
Dependencies are inferred from the claim text.