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US3655440A
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Electrical resistance elements, their composition and method of manufacture
Assignee: CTS Corp
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Filing: 1969-03-03
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Granted: 1972-04-11
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Expires: 1989-03-03
Abstract
Abstract An electrically nonconductive crystal growth controlling agent comprising submicron inert particles is mixed with a crystalline conductive phase comprising an oxide of Ruthenium or Iridium, a vehicle, and a moisture impervious binder with which the inert particles will not react and in which the inert particles will not dissolve to any appreciable extent at elevated temperatures. After being applied to a high temperature-resistant, electrically nonconductive substrate, the composition is fired at elevated temperatures for a sufficient period of time to permit the crystals of the conductive phase to grow until an equilibrium condition is reached. This condition is determined in part by the crystal growth controlling agent. Upon cooling, the binder bonds together a composite mass comprising an inert intersticed matrix made up of the crystal growth controlling agent and the crystalline conductive phase which forms an interstitial mass within the interstices of the matrix. The method comprises the steps of thoroughly mixing the above-identified materials, applying a layer of the mixture to the substrate, and firing the substrate and layer of material for 45 to 60 minutes to a preferred peak temperature in the range of 975*-1025* C. During the firing cycle the crystals of the conductive phase increase in size until further growth is limited by the crystal growth controlling agent.
Inventors
- 👤 Lynn J Brady
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 10:43
CPC Classifications
H; H01; H01C; H01C17/00; H01C17/06; H01C17/065; H01C17/06506; H01C17/06513; H01C17/06533; H01C17/0654; Y; Y10; Y10S; Y10S148/00; Y10S148/051; Y10T; Y10T428/00; Y10T428/26; Y10T428/268
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
97 words
A resistance composition for making resistance elements having a resistance greater than 100 ohms and comprising a glass vitreous binder, at least 2 percent, by weight of solids of the composition, of conductive crystals selected from the group consisting of Ru compounds and Ir compounds that undergo crystalline growth and increase in size in a molten binder environment, and means for controlling the crystalline binder environment, and means for controlling the crystalline growth of the conductive crystals in a molten binder environment, said means comprising at least 1 1/2 percent by weight of solids of the composition.
Claim 2
Dependent Claim
22 words
The composition of claim 2 wherein the conductive crystals comprise a compound selected from the group consisting of PdO, RuO2 and IrO2.
Claim 3
Dependent Claim
34 words
The composition of claim 2 wherein the means for controlling the growth of the conductive crystals comprises particles of inert noncolloidal chemically unreactive material having an average particle size of less than 10 microns.
Claim 4
Dependent Claim
23 words
The composition of claim 4 wherein the inert material comprises a refractory material selected from the group consisting of alumina and barium ferrite.
Claim 5
Dependent Claim
24 words
The composition of claim 4 wherein the particles of inert material comprise from 3 to 16 percent by weight of solids of said composition.
Claim 6
Dependent Claim
22 words
The composition of claim 6 wherein the conductive crystals comprise a compound selected from the group consisting of PdO, RuO2 and IrO2.
Claim 7
Dependent Claim
73 words
A resistance element having a resistance greater than 100 ohms and comprising an intersticed inert matrix, an interstitial mass of a conductive phase comprising conductive crystals selected from the group consisting of Ru compounds and Ir compounds disposed within said matrix, said matrix comprising inert noncolloidal chemically unreactive crystal growth controlling particles bounding the conductive crystals and spacing adjacent ones of said crystals, and a glass vitreous binder bonding together the composite mass.
Claim 8
Dependent Claim
21 words
The resistance element of claim 8 wherein the conductive phase comprises crystals having a size of from 40 to 80 microns.
Claim 9
Dependent Claim
37 words
The resistance element of claim 8 wherein the inert particles comprise from 1 1/2 to 30 percent by weight of the element, and the conductive crystals comprise from 2 to 60 percent by weight of the element.
Claim 10
Dependent Claim
22 words
The resistance element of claim 8 wherein the crystal growth controlling particles have an average particle size of less than 20 microns.
Claim 11
Dependent Claim
23 words
The resistance element of claim 8 wherein the conductive crystals comprise a compound selected from the group consisting of PdO, RuO2 and IrO2.
Claim 12
Dependent Claim
14 words
The resistance element of claim 8 wherein the conductive crystals comprises a Pd compound.
Claim 13
Dependent Claim
64 words
The resistance element of claim 8 wherein the crystal growth controlling particles have an average particle size of from one-tenth micron to 10 microns and comprise from 3 to 16 percent, by weight, of the element, and wherein the conductive phase comprises crystals having a size of from 40 to 80 microns and comprises from 10 to 50 percent, by weight, of the element.
Claim 14
Dependent Claim
146 words
A resistance element having a resistance greater than 100 ohms and comprising an intersticed inert matrix, an interstitial mass of a conductive phase comprising conductive crystals comprising a compound selected from the group consisting of RuO2, IrO2, and PdO disposed within said matrix, said matrix comprising inert noncolloidal chemically unreactive crystal growth controlling particles comprising a refractory material selected from the group consisting of alumina and barium ferrite bounding the conductive crystal and spacing adjacent ones of said crystals, the crystal growth controlling particles having an average particle size of from one-tenth micron to 10 microns and comprising from 3 to 16 percent, by weight, of the element, and wherein the conductive phase comprises crystals having a size of from 40 to 80 microns and comprises from 10 to 50 percent, by weight, of the element, and a glass vitreous binder bonding together the composite mass.
Claim 15
Independent Claim
102 words
A method of forming an electrical resistance element comprising the steps of: mixing together a binder, a conductive phase comprising crystals of a predetermined average size selected from the group consisting of Ru compounds and Ir compounds, particles of inert material having a predetermined average size, and a vehicle to provide a resistance composition, forming an unfired resistance element from the composition, firing the resistance element to a temperature of at least 760* C. to increase the size of crystals in the conductive phase, controlling the amount of size increase of said crystals in the conductive phase, and cooling the resistance element.
Claim 16
Independent Claim
126 words
A method of forming an electrical resistance element comprising the steps of: mixing together a binder, a conductive phase comprising crystals of a predetermined average size selected from the group consisting of Ru compounds and Ir compounds, particles of inert material having a predetermined average size, and a vehicle to provide a resistance composition, forming an unfired resistance element from the composition, applying a layer of the composition to a high temperature resistant electrically nonconductive substrate, firing the resistance element for a period of time in excess of 45 minutes to a temperature of at least 760* C. to increase the size of crystals in the conductive phase, controlling the amount of size increase of said crystals in the conductive phase, and cooling the resistance element.
Claim 17
Independent Claim
158 words
A method of forming an electrical resistance element comprising an intersticed matrix of inert particles, an interstitial mass of conductive crystals selected from the group consisting of Ru compounds and Ir compounds disposed within said matrix, and a binder bonding together the composite mass, said method comprising the steps of mixing together 2 to 60 parts by weight of conductive crystals that have a predeterminable average size and that increase in size in a molten binder environment, 1 1/2 to 30 parts by weight of particles of an inert material, a moisture impervious binder, and a vehicle to provide a resistance composition, forming a portion of the composition into an unfired resistance element, liquefying the binder in said resistance element and promoting growth of conductive crystals in said resistance element, limiting the growth of said conductive crystals with the particles of inert material, and solidifying the binder to bond together the particles of inert material and conductive crystals.
Claim 18
Independent Claim
173 words
A method of forming an electrical resistance element comprising an intersticed matrix of inert particles, an interstitial mass of conductive crystals disposed within said matrix, and a binder bonding together the composite mass, said method comprising the steps of mixing together 2 to 60 parts by weight of conductive crystals that have a predeterminable average size and that increaSe in size in a molten binder environment, 1 1/2 to 30 parts by weight of particles of an inert material, a moisture impervious binder, and a vehicle to provide a resistance composition, forming a portion of the composition into an unfired resistance element, applying said portion to a high temperature resistance substrate, liquefying the binder in said resistance element by firing the resistance element for an extended period of time and at an elevated temperature and promoting growth of said conductive crystals in said resistance element, limiting the growth of said conductive crystals with the particles of inert material, and cooling the binder to bond together the particles of inert material and conductive crystals.
Claim 19
Independent Claim
164 words
A method of forming an electrical resistance element comprising an intersticed matrix of inert particles, an interstitial mass of conductive crystals disposed within said matrix, and a binder bonding together the composite mass, said method comprising the steps of mixing together 2 to 60 parts by weight of conductive crystals that have a predeterminable average size and that increase in size in a molten binder environment, 1 1/2 to 30 parts by weight of particles of an inert material, a moisture impervious binder, and a vehicle to provide a resistance composition, forming a portion of the composition into an unfired resistance element, applying said portion to a high temperature resistance substrate, liquefying the binder in said resistance element by firing the resistance element to a temperature of at least 975* C. and for at least 45 minutes promoting growth of conductive crystals in said resistance element, limiting the growth of said conductive crystals with the particles of inert material, and cooling the resistance element.
Claim 20
Independent Claim
131 words
A method of making an electrical resistance element comprising conductive crystals, inert particles, and a binder and characterized by a high sheet resistance, a Sheet VCR of less than 400 parts per million per volt, and a voltage withstanding ability in excess of 1,000 volts per inch, said method comprising the steps of making a resistance composition by mixing together conductive crystals selected from the group consisting of Ru compounds and Ir compounds, inert particles and binder, forming an unfired resistance element from the composition, firing the resistance element to a temperature of at least 760* C. to provide a molten binder environment for the inert particles and conductive crystals in order to attain growth of the conductive crystals until an equilibrium condition is approached, and thereafter cooling the resistance element.
References Cited (Backward Citations)
US3441516A
Cited
US3450545A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-11 | 1975-10-11 | 1976-04-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-11 | 1979-10-11 | 1980-04-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-11 | 1983-10-11 | 1984-04-11 | $7700.00 | Window Closed / Lapsed |