US3989874A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resistance material with colloidal AlOOH
Assignee: Sprague Electric Co
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Filing: 1975-01-23
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Granted: 1976-11-02
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Expires: 1995-01-23
Abstract
Abstract In a noble-metal containing resistor paste, there is added a quantity of colloidal aluminum oxide hydroxide (AlOOH) in order to make an upward adjustment in the TCR of the fired resistor film. The additions of AlOOH have only a small effect on the resistivity and usually causes a downward change in the resistivity value.
Inventors
- 👤 John P. Maher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:13
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/06; H01C17/00; H01C17/06; H01C17/065; H01C17/06506; H01C17/06513; H01C17/06573; H01C17/0658
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
101 words
In a resistance material having an electrically conductive component selected from a noble metal and a noble metal oxide, the improvement comprising the addition therein of colloidal alumina particles having been introduced in the form of colloidal aluminum oxide hydroxide particles, and being uniformly dispersed in said material for the purpose of making the temperature coefficient of resistance more positive, the weight percent of said alumina particles that are present in said resistance material being no less than 0.04% and no more than that required to cause the sheet resistivity of said resistance material to exceed about 17 megohms per square.
Claim 2
Dependent Claim
101 words
In a resistance material having an electrically conductive component selected from a noble metal and a noble metal oxide, the improvement comprising the addition therein of colloidal alumina particles having been introduced in the form of colloidal aluminum oxide hydroxide particles, and being uniformly dispersed in said material for the purpose of making the temperature coefficient of resistance more positive, the weight percent of said alumina particles that are present in said resistance material being no less than 0.04% and no more than that required to cause the sheet resistivity of said resistance material to exceed about 17 megohms per square.
Claim 3
Dependent Claim
13 words
The resistance material of claim 1 additionally having a matrix of glass therein.
Claim 4
Dependent Claim
13 words
The resistance material of claim 1 wherein said aluminum oxide hydroxide is boehmite.
Claim 5
Dependent Claim
24 words
The resistance material of claim 1 additionally having a suppporting ceramic substrate, said resistance material being a layer that is bonded to said substrate.
Claim 6
Dependent Claim
11 words
The resistance material of claim 4 wherein said substrate is glazed.
Claim 7
Dependent Claim
24 words
The resistance material of claim 1 wherein the average of the largest dimensions of said aluminum oxide hydroxide particles is less than 0.05 microns.
Claim 8
Dependent Claim
126 words
In a method for making a layer of resistance material including preparing a resistor ink containing an electrically conductive precursor component selected from a noble metal and a noble metal oxide, applying a layer of said ink to a substrate and firing said ink; the improvement comprising uniformly dispersing in said ink colloidal particles of aluminum oxide hydroxide for the purpose of making the temperature coefficient of resistance of said fired resistance material more positive, the amount of said aluminum oxide hydroxide in weight percent of the combined weight of said alumina and said metal in said ink, being no less than 0.1% and no more than that required to cause the sheet resistivity of said fired resistance material to exceed about 17 megohms per square.
Claim 9
Dependent Claim
126 words
In a method for making a layer of resistance material including preparing a resistor ink containing an electrically conductive precursor component selected from a noble metal and a noble metal oxide, applying a layer of said ink to a substrate and firing said ink; the improvement comprising uniformly dispersing in said ink colloidal particles of aluminum oxide hydroxide for the purpose of making the temperature coefficient of resistance of said fired resistance material more positive, the amount of said aluminum oxide hydroxide in weight percent of the combined weight of said alumina and said metal in said ink, being no less than 0.1% and no more than that required to cause the sheet resistivity of said fired resistance material to exceed about 17 megohms per square.
Claim 10
Dependent Claim
16 words
The method of claim 7 additionally comprising mixing into said ink a quantity of glass frit.
Claim 11
Dependent Claim
19 words
The method of claim 7 wherein said applying of said layer to said substrate is accomplished by screen printing.
Claim 12
Dependent Claim
20 words
The method of claim 7 wherein said conductive precursor component in said ink consists of particles of said noble metal.
Claim 13
Dependent Claim
19 words
The method of claim 7 wherein said conductive precursor component in said ink consists of a noble metal resinate.
References Cited (Backward Citations)
US2915475A
Cited
US3441516A
Cited
US3416960A
Cited
US3450545A
Cited
US3620840A
Cited
US3655440A
Cited
US3868334A
Cited
US3816348A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-11-02 | 1980-05-03 | 1980-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-02 | 1984-05-03 | 1984-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-02 | 1988-05-03 | 1988-11-02 | $7700.00 | Window Closed / Lapsed |