CA2066273C - Solid-state oxygen sensor - Google Patents
Solid-state oxygen sensorInfo
- Publication number
- CA2066273C CA2066273C CA002066273A CA2066273A CA2066273C CA 2066273 C CA2066273 C CA 2066273C CA 002066273 A CA002066273 A CA 002066273A CA 2066273 A CA2066273 A CA 2066273A CA 2066273 C CA2066273 C CA 2066273C
- Authority
- CA
- Canada
- Prior art keywords
- electrode
- stoechiometric
- ceramic oxide
- solid
- oxygen sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/406—Cells and probes with solid electrolytes
- G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases
- G01N27/4075—Composition or fabrication of the electrodes and coatings thereon, e.g. catalysts
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- General Physics & Mathematics (AREA)
- Electrochemistry (AREA)
- Physics & Mathematics (AREA)
- Analytical Chemistry (AREA)
- Molecular Biology (AREA)
- General Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Measuring Oxygen Concentration In Cells (AREA)
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
- Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
Abstract
The invention relates to a solid oxygen sensor consisting of an electrolytical cell, with a first electrode exposed to the atmosphere whose partial oxygen pressure is to be measured, a second electrode exposed to a reference atmosphere and a solid electrolyte in surface contact with both electrodes, the material of the electrolyte being a ceramic oxide or a vitreous phase with pure ion conduction and at least the first electrode containing a non-stoechiometric ceramic oxide. According to the invention, the first electrode consists of a mixture (CERMET) of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, platinum, nickel and chromium. Such a sensor can record the partial oxygen pressure in a wide measuring range and is rather insensitive against poisoning of the electrodes by carbon monoxide or lead.
Description
SOLID-STATE OXYGEN SENSOR
According to the present invention, there is provided a solid oxygen sensor consisting of an electrolytical cell, with a first electrode exposed to the atmosphere whose partial oxygen pressure is to be measured, a second electrode exposed to a reference atmosphere and a solid electrolyte in surface contact with both electrodes, the material of the electrolyte being a ceramic oxide or a vitreous phase with pure ion conduction and at least the first electrode containing a non-stoechiometric ceramic oxide, characterized in that the first electrode consists of a mixture (CERMET) of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, platinum, nickel and chromium.
A non-stoechiometric oxide is a thermally stable system which is clearly different from the stoechiometric composition. Hereinafter, this will mean both sub-stoechiometric and over-stoechiometric systems.
Such an oxygen sensor is known from DE-32 29 931 Al. The two electrodes of this sensor are constituted by non-stoechiometric oxides or mixtures of such compounds, for example Pr02+x, Ce02_x, Tb02_x. The solid electrolyte is a ceramic oxide or a glass phase with pure ion conductivity. Such sensors (Pr02+x is used as electrode material in oxidizing and Ce02_x or Tb02_x is used in reducing atmosphere) are, however, only applicable in restricted measuring ranges.
la Also, one has to take into account a poisoning of the electrodes in particular by carbon monoxide or lead, so that such a sensor, when used for the control of atmospheres con-taining carbon monoxide or of exhaust gas emissions, has only a limited operating time due to poisoning phenomena.
It is thus the aim of the invention to conceive a solid oxygen sensor which permits the measurement of a wide range of partial oxygen pressures, and this as well in a very reducing as in a very oxidizing atmosphere and without an l0 important loss in sensibility or an unacceptable increase in the response delay. The extension of operating time signifies a very high economic gain, since it is thus possible to use one electrode for the measurement of suddenly changing partial oxygen pressures - such as it happens in operation or by accident.
According to the invention, this aim is attained by the fact that the first electrode consists of a mixture of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, plati-num, nickel and chromium.
Preferably, the metal weight in the first electrode lies between 10 and 30g, in particular 20$ of the total weight.
The invention will now be described more in detail by means of some embodiments.
A solid oxygen sensor essentially consists in two electrodes and a solid electrolyte therebetween. The electro-des are connected to a measuring circuit, the voltage dif-ference between the two electrodes defining the difference of the partial oxygen pressure affecting the two electrodes respectively.
Often, the sensor is in the shape of a tube closed on one side, the inner wall of which constitutes the reference electrode and the outer wall of which constitutes the measur-ing electrode. The area between these walls is at least par-tially filled by the solid electrolyte. Inside the tube there is a reference gas of given composition, for example pure oxygen, air or a known gas mixture, such as CO/C02 or H2/H20.
The reference atmosphere can also be constituted by a mixture of metals and metal oxides such as Fe/Fe0 or Ni/NiO.
The outer side of the tube is submitted to the atmo-sphere the partial oxygen pressure of which is to be measured.
Of course, the invention is not limited to this shape of a sensor. Thus, the sensor could also be an even platelet, which constitutes the partition between two chambers, i.e. a reference chamber and a measurement chamber.
The reference electrode can, like in the case of the above mentioned document, be constituted by a noble metal or a ceramic oxide or by a mixture thereof.
The electrode facing the atmosphere to be analysed is constituted, according to the invention, by a mixture of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, plati-num, nickel and chromium, and the ceramic oxide being chosen from the group containing the following compounds: Pr02+x' Ce02-x, Tb02+x' LaCr03, Lal-xSrxCr03. It is also possible to admix two different ceramic oxides to the metals, one being over-stoechiometric and the other sub-stoechiometric, for example Ce02-x and Pr02+x' This takes into account a highly reducing as well as a highly oxidizing atmosphere. Further, it is also possible to use solid solutions of these oxides, for example CeyPrl-y 2+x' For x there is chosen a value between 0 and 0,2. A mixture of ceramic and metals is called "cermet".
The oxygen sensor according to the invention has a wide field of application in the supervision of metallurgical processes, in the operation of vapour turbines and ovens, in the exhaust gases control of vehicles and in air supervision.
The measuring gas for the partial oxygen pressure can lie between 10 30 and 1 atm.
According to the present invention, there is provided a solid oxygen sensor consisting of an electrolytical cell, with a first electrode exposed to the atmosphere whose partial oxygen pressure is to be measured, a second electrode exposed to a reference atmosphere and a solid electrolyte in surface contact with both electrodes, the material of the electrolyte being a ceramic oxide or a vitreous phase with pure ion conduction and at least the first electrode containing a non-stoechiometric ceramic oxide, characterized in that the first electrode consists of a mixture (CERMET) of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, platinum, nickel and chromium.
A non-stoechiometric oxide is a thermally stable system which is clearly different from the stoechiometric composition. Hereinafter, this will mean both sub-stoechiometric and over-stoechiometric systems.
Such an oxygen sensor is known from DE-32 29 931 Al. The two electrodes of this sensor are constituted by non-stoechiometric oxides or mixtures of such compounds, for example Pr02+x, Ce02_x, Tb02_x. The solid electrolyte is a ceramic oxide or a glass phase with pure ion conductivity. Such sensors (Pr02+x is used as electrode material in oxidizing and Ce02_x or Tb02_x is used in reducing atmosphere) are, however, only applicable in restricted measuring ranges.
la Also, one has to take into account a poisoning of the electrodes in particular by carbon monoxide or lead, so that such a sensor, when used for the control of atmospheres con-taining carbon monoxide or of exhaust gas emissions, has only a limited operating time due to poisoning phenomena.
It is thus the aim of the invention to conceive a solid oxygen sensor which permits the measurement of a wide range of partial oxygen pressures, and this as well in a very reducing as in a very oxidizing atmosphere and without an l0 important loss in sensibility or an unacceptable increase in the response delay. The extension of operating time signifies a very high economic gain, since it is thus possible to use one electrode for the measurement of suddenly changing partial oxygen pressures - such as it happens in operation or by accident.
According to the invention, this aim is attained by the fact that the first electrode consists of a mixture of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, plati-num, nickel and chromium.
Preferably, the metal weight in the first electrode lies between 10 and 30g, in particular 20$ of the total weight.
The invention will now be described more in detail by means of some embodiments.
A solid oxygen sensor essentially consists in two electrodes and a solid electrolyte therebetween. The electro-des are connected to a measuring circuit, the voltage dif-ference between the two electrodes defining the difference of the partial oxygen pressure affecting the two electrodes respectively.
Often, the sensor is in the shape of a tube closed on one side, the inner wall of which constitutes the reference electrode and the outer wall of which constitutes the measur-ing electrode. The area between these walls is at least par-tially filled by the solid electrolyte. Inside the tube there is a reference gas of given composition, for example pure oxygen, air or a known gas mixture, such as CO/C02 or H2/H20.
The reference atmosphere can also be constituted by a mixture of metals and metal oxides such as Fe/Fe0 or Ni/NiO.
The outer side of the tube is submitted to the atmo-sphere the partial oxygen pressure of which is to be measured.
Of course, the invention is not limited to this shape of a sensor. Thus, the sensor could also be an even platelet, which constitutes the partition between two chambers, i.e. a reference chamber and a measurement chamber.
The reference electrode can, like in the case of the above mentioned document, be constituted by a noble metal or a ceramic oxide or by a mixture thereof.
The electrode facing the atmosphere to be analysed is constituted, according to the invention, by a mixture of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, plati-num, nickel and chromium, and the ceramic oxide being chosen from the group containing the following compounds: Pr02+x' Ce02-x, Tb02+x' LaCr03, Lal-xSrxCr03. It is also possible to admix two different ceramic oxides to the metals, one being over-stoechiometric and the other sub-stoechiometric, for example Ce02-x and Pr02+x' This takes into account a highly reducing as well as a highly oxidizing atmosphere. Further, it is also possible to use solid solutions of these oxides, for example CeyPrl-y 2+x' For x there is chosen a value between 0 and 0,2. A mixture of ceramic and metals is called "cermet".
The oxygen sensor according to the invention has a wide field of application in the supervision of metallurgical processes, in the operation of vapour turbines and ovens, in the exhaust gases control of vehicles and in air supervision.
The measuring gas for the partial oxygen pressure can lie between 10 30 and 1 atm.
Claims (3)
1. A solid oxygen sensor consisting of an electrolytical cell, with a first electrode exposed to the atmosphere whose partial oxygen pressure is to be measured, a second electrode exposed to a reference atmosphere and a solid electrolyte in surface contact with both electrodes, the material of the electrolyte being a ceramic oxide or a vitreous phase with pure ion con-duction and at least the first electrode containing a non-stoechiometric ceramic oxide, characterized in that the first electrode consists of a mixture (CERMET) of at least one non-stoechiometric ceramic oxide and a metal, the latter being chosen from the group constituted by gold, platinum, nickel and chromium.
2. A sold oxygen sensor according to claim 1, characterized in that the ceramic oxide is chosen from the group containing the following compounds: Pr O2+x' Tb O2-x, Ce O2-x, LaCr O3, La l-x Sr x CrO3, with 0 ~ x ~ 0,2, or mechanical mixtures of a sub- and an over-stoechiometric oxide or a solid solution of both.
3. A solid oxygen sensor according to one of claims 1 to 2, characterized in that the metal weight in the first electrode lies between 10 and 30% of the total weight.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| LU87596A LU87596A1 (en) | 1989-09-25 | 1989-09-25 | SOLID OXYGEN SENSOR |
| LU87596 | 1989-09-25 | ||
| PCT/EP1990/001615 WO1991004485A1 (en) | 1989-09-25 | 1990-09-24 | Solid-state oxygen sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2066273A1 CA2066273A1 (en) | 1991-03-26 |
| CA2066273C true CA2066273C (en) | 2001-06-12 |
Family
ID=19731187
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002066273A Expired - Fee Related CA2066273C (en) | 1989-09-25 | 1990-09-24 | Solid-state oxygen sensor |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP0420107B2 (en) |
| JP (1) | JP3010376B2 (en) |
| AT (1) | ATE101719T1 (en) |
| AU (1) | AU637147B2 (en) |
| CA (1) | CA2066273C (en) |
| DE (1) | DE59004598D1 (en) |
| DK (1) | DK0420107T3 (en) |
| ES (1) | ES2049882T5 (en) |
| GR (1) | GR3025334T3 (en) |
| IE (1) | IE64606B1 (en) |
| LU (1) | LU87596A1 (en) |
| PT (1) | PT95406B (en) |
| WO (1) | WO1991004485A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR102225917B1 (en) * | 2018-08-22 | 2021-03-10 | 곽태영 | Posture correction device |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2738756A1 (en) * | 1977-08-27 | 1979-03-01 | Bbc Brown Boveri & Cie | Electrochemical cell for determining oxygen in exhaust gas - using reference electrode coated with metal oxide catalyst layer |
| EP0006989B1 (en) * | 1978-06-12 | 1983-06-15 | Corning Glass Works | Hot gas measuring device |
| DE2837118C2 (en) * | 1978-08-25 | 1982-05-19 | Dornier System Gmbh, 7990 Friedrichshafen | Porous oxide electrodes for high temperature electrochemical cells |
| IT1149039B (en) * | 1981-08-10 | 1986-12-03 | Euratom | SOLID STATE OXOGEN SENSOR |
| US4562124A (en) * | 1985-01-22 | 1985-12-31 | Westinghouse Electric Corp. | Air electrode material for high temperature electrochemical cells |
| DE3611291A1 (en) * | 1986-04-04 | 1987-10-15 | Dornier System Gmbh | MANUFACTURE OF LONG-TERM-RESISTANT OXYGEN ELECTRODES FOR ELECTROLYSIS CELLS WITH FIXED ELECTROLYTE |
-
1989
- 1989-09-25 LU LU87596A patent/LU87596A1/en unknown
-
1990
- 1990-09-10 IE IE328890A patent/IE64606B1/en not_active IP Right Cessation
- 1990-09-24 DE DE90118314T patent/DE59004598D1/en not_active Expired - Fee Related
- 1990-09-24 AT AT90118314T patent/ATE101719T1/en not_active IP Right Cessation
- 1990-09-24 DK DK90118314.5T patent/DK0420107T3/en active
- 1990-09-24 AU AU64155/90A patent/AU637147B2/en not_active Ceased
- 1990-09-24 JP JP2513267A patent/JP3010376B2/en not_active Expired - Fee Related
- 1990-09-24 PT PT95406A patent/PT95406B/en active IP Right Grant
- 1990-09-24 EP EP90118314A patent/EP0420107B2/en not_active Expired - Lifetime
- 1990-09-24 ES ES90118314T patent/ES2049882T5/en not_active Expired - Lifetime
- 1990-09-24 WO PCT/EP1990/001615 patent/WO1991004485A1/en active Application Filing
- 1990-09-24 CA CA002066273A patent/CA2066273C/en not_active Expired - Fee Related
-
1997
- 1997-11-11 GR GR970402976T patent/GR3025334T3/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| EP0420107A1 (en) | 1991-04-03 |
| ATE101719T1 (en) | 1994-03-15 |
| IE64606B1 (en) | 1995-08-23 |
| AU637147B2 (en) | 1993-05-20 |
| PT95406B (en) | 1998-06-30 |
| JP3010376B2 (en) | 2000-02-21 |
| EP0420107B1 (en) | 1994-02-16 |
| AU6415590A (en) | 1991-04-18 |
| JPH06502910A (en) | 1994-03-31 |
| DK0420107T3 (en) | 1994-05-24 |
| IE903288A1 (en) | 1991-04-10 |
| EP0420107B2 (en) | 1997-10-22 |
| ES2049882T3 (en) | 1994-05-01 |
| ES2049882T5 (en) | 1998-01-01 |
| LU87596A1 (en) | 1991-05-07 |
| CA2066273A1 (en) | 1991-03-26 |
| PT95406A (en) | 1992-06-30 |
| WO1991004485A1 (en) | 1991-04-04 |
| GR3025334T3 (en) | 1998-02-27 |
| DE59004598D1 (en) | 1994-03-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |