US4186071A
Expired / Lapsed
US
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Process for producing oxygen gas sensor elements
Assignee: Bendix Corp
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Filing: 1979-01-19
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Granted: 1980-01-29
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Expires: 1999-01-19
Abstract
Abstract An activated oxygen gas sensor element having an increased voltage output under rich gas conditions, short switching response and reduced internal resistance is produced by chemically treating the inner conductive catalyst electrode of the sensor element with an inorganic acid or acid salt and current activating the outer conductive catalyst electrode by applying a direct current to the sensor element, with the outer electrode as a cathode, while the outer electrode is at an elevated temperature and in the presence of a neutral or inert atmosphere. Air may be used as the atmosphere in contact with the outer electrode during the current activation provided that the sensor is subjected to a subsequent reheating step to provide the desired results.
Inventors
- 👤 Donald J. Romine
- 👤 Donald C. Davis
- 👤 Phillip R. Woodruff
- 👤 Ching T. Young
- 👤 James D. Bode
- 👤 Tseng Y. Tien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:18
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/407; G01N27/4075; H; H01; H01M; H01M4/00; H01M4/86; H01M4/90; H01M4/9041; H01M4/905; H01M4/9058; H01M4/92; H01M2004/8678; H01M2004/8689; H01M8/00; H01M8/10; H01M8/12; H01M2008/1293; H01M2300/00; H01M2300/0017; H01M2300/0065; H01M2300/0068; H01M2300/0071; H01M2300/0074; H01M2300/0082; Y; Y02; Y02E; Y02E60/00; Y02E60/30; Y02E60/50
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
164 words
A process for producing an activated oxygen gas sensor element having an increased voltage output under rich gas conditions, shortened switching response time and reduced internal resistance, wherein the sensor element comprises a solid electrolyte body having an inner conductive catalyst electrode on the inner surface and an outer conductive catalyst electrode on the outer surface thereof, comprising: (a) contacting said inner conductive catalyst electrode with an acidic reactant selected from the group consisting of inorganic acids and acid salts; (b) applying a direct current to the sensor element, with said outer conductive catalyst electrode as a cathode, while subjecting said outer conductive catalyst electrode to a neutral or inert atmosphere at an elevated temperature in excess of 500° C., the current density thereof being at least 5 milliamperes per square centimeter of the planar surface of said outer conductive catalyst electrode; and (c) maintaining said outer electrode, after cessation of said current, at the elevated temperature for a period of time for recovery.
Claim 2
Dependent Claim
164 words
A process for producing an activated oxygen gas sensor element having an increased voltage output under rich gas conditions, shortened switching response time and reduced internal resistance, wherein the sensor element comprises a solid electrolyte body having an inner conductive catalyst electrode on the inner surface and an outer conductive catalyst electrode on the outer surface thereof, comprising: (a) contacting said inner conductive catalyst electrode with an acidic reactant selected from the group consisting of inorganic acids and acid salts; (b) applying a direct current to the sensor element, with said outer conductive catalyst electrode as a cathode, while subjecting said outer conductive catalyst electrode to a neutral or inert atmosphere at an elevated temperature in excess of 500° C., the current density thereof being at least 5 milliamperes per square centimeter of the planar surface of said outer conductive catalyst electrode; and (c) maintaining said outer electrode, after cessation of said current, at the elevated temperature for a period of time for recovery.
Claim 3
Dependent Claim
20 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said atmosphere contains moisture.
Claim 4
Dependent Claim
22 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said atmosphere consists essentially of nitrogen.
Claim 5
Dependent Claim
42 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said contacting of the inner electrode with said acidic reactant is effected and thereafter the application of said direct current to the outer electrode is effected.
Claim 6
Dependent Claim
42 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said application of the direct current to the outer electrode is effected and thereafter said contacting of the inner electrode with said acidic reactant is effected.
Claim 7
Dependent Claim
34 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said direct current is applied while the sensor element is at an elevated temperature of between 500°-1200° C.
Claim 8
Dependent Claim
40 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said direct current is applied at a current density of between 5-1000 milliamperes per square centimeter of the planar surface of said outer electrode.
Claim 9
Dependent Claim
30 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said direct current is applied for a period of time of between 2-30 minutes.
Claim 10
Dependent Claim
28 words
The process for producing an activated oxygen gas sensor element as defined in claim 1 wherein said period of time for recovery is in excess of 3 minutes.
Claim 11
Dependent Claim
14 words
The activated oxygen gas sensor element produced according to the process of claim 1.
Claim 12
Dependent Claim
154 words
A process for producing an activated oxygen gas sensor element having an increased voltage output under rich gas conditions, shortened switching response time and reduced internal resistance, wherein the sensor element comprises a zirconium dioxide body having an inner platinum electrode on the inner surface and an outer platinum electrode on the outer surface thereof, comprising: (a) contacting said inner platinum electrode with an acidic reactant selected from the group consisting of inorganic acids and acid salts; (b) applying a direct current to the sensor element, with said outer platinum electrode as a cathode, while subjecting said outer platinum electrode to a moisture-containing nitrogen atmosphere at an elevated temperature between 600°-900° C., the current density thereof being between 20-150 milliamperes per square centimeter of the planar surface of said outer platinum electrode; and (c) maintaining said outer electrode, after cessation of said current, at the elevated temperature for a period of time for recovery.
Claim 13
Dependent Claim
154 words
A process for producing an activated oxygen gas sensor element having an increased voltage output under rich gas conditions, shortened switching response time and reduced internal resistance, wherein the sensor element comprises a zirconium dioxide body having an inner platinum electrode on the inner surface and an outer platinum electrode on the outer surface thereof, comprising: (a) contacting said inner platinum electrode with an acidic reactant selected from the group consisting of inorganic acids and acid salts; (b) applying a direct current to the sensor element, with said outer platinum electrode as a cathode, while subjecting said outer platinum electrode to a moisture-containing nitrogen atmosphere at an elevated temperature between 600°-900° C., the current density thereof being between 20-150 milliamperes per square centimeter of the planar surface of said outer platinum electrode; and (c) maintaining said outer electrode, after cessation of said current, at the elevated temperature for a period of time for recovery.
Claim 14
Dependent Claim
181 words
A process for producing an activated oxygen gas sensor element having an increased voltage output under rich gas conditions, shortened switching response time and reduced internal resistance, wherein the sensor element comprises a solid electrolyte body having an inner conductive catalyst electrode on the inner surface and an outer conductive catalyst electrode on the outer surface thereof, comprising: (a) contacting said inner conductive catalyst electrode with an acidic reactant selected from the group consisting of inorganic acids and acid salts; (b) applying a direct current to the sensor element, with said outer conductive catalyst electrode as a cathode, while subjecting said outer conductive catalyst electrode to an elevated temperature in excess of 500° C., in the presence of air, the current density of said direct current being at least 5 milliamperes per square centimeter of the planar surface of said outer conductive catalyst electrode; (c) maintaining said outer electrode, after cessation of said current, at said elevated temperature for a period of time for recovery; and (d) subsequently reheating said sensor element to a temperature in the range of 700°-900° C.
Claim 15
Dependent Claim
181 words
A process for producing an activated oxygen gas sensor element having an increased voltage output under rich gas conditions, shortened switching response time and reduced internal resistance, wherein the sensor element comprises a solid electrolyte body having an inner conductive catalyst electrode on the inner surface and an outer conductive catalyst electrode on the outer surface thereof, comprising: (a) contacting said inner conductive catalyst electrode with an acidic reactant selected from the group consisting of inorganic acids and acid salts; (b) applying a direct current to the sensor element, with said outer conductive catalyst electrode as a cathode, while subjecting said outer conductive catalyst electrode to an elevated temperature in excess of 500° C., in the presence of air, the current density of said direct current being at least 5 milliamperes per square centimeter of the planar surface of said outer conductive catalyst electrode; (c) maintaining said outer electrode, after cessation of said current, at said elevated temperature for a period of time for recovery; and (d) subsequently reheating said sensor element to a temperature in the range of 700°-900° C.
Claim 16
Dependent Claim
20 words
The process for producing an activated oxygen gas sensor element as defined in claim 12 wherein said electrodes comprise platinum.
Claim 17
Dependent Claim
20 words
The process for producing an activated oxygen gas sensor element as defined in claim 12 wherein said air contains moisture.
Claim 18
Dependent Claim
13 words
The activated oxygen gas sensor produced according to the process of claim 12.
References Cited (Backward Citations)
US4136000A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-01-28 | 1983-07-30 | 1984-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-01-28 | 1987-07-30 | 1988-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-01-28 | 1991-07-30 | 1992-01-29 | $7700.00 | Window Closed / Lapsed |