Cts Corporation

Charles C Kuo

Terry R Bloom

Tom O Martin

A surge resistor has a thick film resistance element containing alloyed nickel-chromium mixed with alloyed copper-nickel and less than twenty percent by weight glass. The surge resistor overcomes the limitations of the prior art by offering the unexpected advantage of improved power surge handling capacity. A thick film composition used to form the surge resistor, which also includes screening agent, is fired at temperatures generally below 1,000.degree. C., yielding a highly stable and well adhered electrical resistor. In addition to improved surge capability, the composition offers lower cost and less migration than the precious metal alternatives that the composition replaces. Additional inventive surge resistors include copper-manganese and nickel-chromium in combination with less than twenty percent by weight glass.

Low resistance paints for surge applications using nickel-chromium alloy

Base metal resistors based on a new approach to alloy formation of nickel and chromium metals are presented that are rugged and offer excellent stability. Fine particle size nickel and chromium powders together with fluxing agents are blended together in a preselected ratio with a glass fret and screening agent. The composition is subsequently printed and fired in a nitrogen furnace at approximately 900.degree. C. to 930.degree. C. These resistors are compatible with other prior art base metal conductors, resistors and dielectrics.

Process of producing a low TCR surge resistor using a nickel chromium

Base metal resistors based on a new approach to alloy formation of nickel and chromium metals are presented that are rugged and offer excellent stability. Fine particle size nickel and chromium powders together with fluxing agents are blended together in a preselected ratio with a glass frit and screening agent. The composition is subsequently printed and fired in a nitrogen furnace at approximately 900.degree. C. to 930.degree. C. These resistors are compatible with other prior art base metal conductors, resistors and dielectrics.

A low TCR cermet composition of pre-alloyed nickel-chromium may be blended with pre-alloyed titanium silicide to form an extended range low TCR cermet composition. Additionally, the nickel-chromium cermet composition may also be blended with a titanium silicide composition to form a blending pair that allows for unlimited resistivity control over a decade of resistance. Other low TCR base metal alloys in addition to nickel-chromium are further contemplated.

Base metal resistors

Fine copper and nickel powders are well mixed in a preselected ratio with bonding agents and carriers as appropriate. The composition then may be patterned upon a substrate by screen printing and subsequent firing in a nitrogen atmosphere to produce a low sheet resistance, low TCR electrical resistor. Various alloy powders, inert materials, and glass frits may be used depending upon the desired characteristics.

Method of manufacturing a low sheet resistance article

A pre-reacted resistor paint is disclosed, wherein a base metal powder, such as SnO.sub.2 is coated with a resinate solution, such as Co and Mn resinates and fired in a reducing atmosphere to form a pre-reacted conductive powder for subsequent mixing with a glass frit and a screening agent to blend a pre-reacted resistive paint, for subsequent screening onto a substrate and firing in an inert atmosphere to form a base metal resistor therefrom. Two mixtures of resistive paint are disclosed. The first resistive paint exhibiting a sheet resistivity in the range from 5,000 through 20,000 ohms per square; and the second resistive paint exhibiting a sheet resistivity in the range from 50,000 through 300,000 ohms per square. The first and second resistive paints may be blended to provide a base metal resistive paint exhibiting a sheet resistivity in the range from 5,000 through 300,000 ohms per square, with a TCR within .+-.200 ppm/.degree.C.

Pre-reacted resistor paint, and resistors made therefrom

A thick film resistor paint is disclosed, wherein a base metal powder, such as tin oxide powder, is coated with a resinate solution, such as an Mn resinate solution, and the resinate coated powder thus formed is prefired in a reducing atmosphere to form a pre-reacted conductive powder. The pre-reacted conductive powder is then mixed with a glass frit, an oxide of hafnium, and a screening agent to form a thick film resistive paint having a sheet resistivity of from 500,000 ohms to 5 megohms per square. The resistive paint is subsequently screened upon a substrate and fired in an inert atmosphere, preferably at 900.degree. C..+-.20.degree. C., to form a thick film base metal resistor exhibiting a combined TCR within .+-.200 ppm/.degree.C. The glass frit is preferably a tantala glass frit.

Megohm resistor paint and resistors made therefrom

Base metal resistive paints, resistors made therefrom and method for making the resistive paint are disclosed. The base metal resistive paints comprise 20 to 25% tantala glass frit and 75 to 80% tin oxide, ground to a particle size of ten microns or less; and well mixed with 25 to 35% screening agent for subsequent screening upon a suitable substrate, and firing in an inert atmosphere at a peak temperature of about 900.degree. C. The tantala glass frit preferably comprises 5 to 25% tantatum oxide. The tin oxide is preferably preheated at 450.degree. to 600.degree. C. in the presence of a reducing gas, prior to mixing with the tantala glass frit. The screening agent preferably forms no carbon residue when pyrolytically decomposed in an inert atmosphere during firing.

Base metal resistor

Base metal resistive paints

This invention relates to thick film base metal resistive paints for firing on a substrate to form a resistor having a temperature coefficient of resistance within .+-.100 ppm/.degree.C., while providing a means to selectively blend the resistive paint to provide a wide range of decade resistivities from less than 10 ohms/square to more than 1K ohms/square. The sheet resistance and TCR are controlled by mixing a glass frit from at least one of a first and second glass material; with TiSi.sub.2 ; and at least one of Ti.sub.5 Si.sub.3 and AL.sub.2 O.sub.3 ; and a screening agent, for subsequent screening onto a substrate and firing in an inert atmosphere at a peak temperature of about 900.degree. C. The first glass material comprises, by weight, 5 to 10% SiO.sub.2 ; 30 to 50% BaO; 40 to 60% B.sub.2 O.sub.3 and 1 to 5% CuO. The second glass material comprises, by weight, 50 to 70% B.sub.2 O.sub.3 ; 25 to 45% SrO; and 2 to 10% SiO.sub.2. The quantity of the glass material is increased to raise sheet resistance in ohms per square, and to lower the value of the TCR. The quantity of TiSi.sub.2 is increased to lower sheet resistance in ohms per square, and to raise the TCR. The quantity to TiSi.sub.2 is increased to lower sheet resistance in ohms per square, and to raise the TCR. The quantity of Ti.sub.5 Si.sub.3 is increased to lower the sheet resistance in ohms per square, and to lower the TCR. The quantity of Al.sub.2 O.sub.3 is increased to raise the sheet resistance in ohms per square, and to lower the TCR. The screening agent preferably has no carbon residue when pyrolytically decomposed during firing in an inert atmosphere.

Thick film resistive paint and resistors made therefrom

A copper conductive paint for use on a porcelanized metal substrate, which comprises a powder mixture of 82 to 98.5% copper, 0.5 to 12% copper hydroxide, and 1 to 6% non-reducable borosilicate glass frit. 75 to 90 percent of the powder mixture is blended with 10 to 25 percent screening agent to form the copper conductive paint herein disclosed. The copper conductive paint is then screened and fired upon a porcelainized metal substrate in an inert atmosphere at approximately 900.degree. C. to form a copper conductor exhibiting improved adhesion characteristics.

Copper conductive paint for porcelainized metal substrates

A method for producing a thick film circuit (30) including a copper conductor pattern (19), thereby obviating the need for expensive precious metal compositions. In the process, a fritted copper paint (16) is applied to a ceramic substrate (18) and fired at a temperature of 850.degree. C. to 950.degree. C. and is oxidized. Concurrently, the paint (16) is adhesively joined to the nonreactive and nonconductive ceramic substrate (18). Next, a resistor paint (20) is applied in overlapping relationship with the air-heated copper conductor pattern (19) and fired at 850.degree. C. to 950.degree. C. The entire unit is then fired in a reducing atmosphere at a temperature of 260.degree. C. to 450.degree. C. to reduce the oxidized copper. The air-fired resistor pattern (21) can either be protected by a coating (40) or unprotected during the reducing atmosphere firing. The essential ingredients of the copper paint (16) are a frit (12) that is non-reducible under a hydrogen atmosphere, a copper powder (10) and a suitable screening agent ( 14). In this new and improved three-step firing process, the copper conductors are compatible with existing ruthenium base resistors.

Growing community of inventors

Elkhart, IN, United States of America

Charles C Kuo