EP0748441A1 - Sonde electrochimique de mesure a element capteur sans potentiel - Google Patents

Sonde electrochimique de mesure a element capteur sans potentiel

Info

Publication number
EP0748441A1
EP0748441A1 EP95938351A EP95938351A EP0748441A1 EP 0748441 A1 EP0748441 A1 EP 0748441A1 EP 95938351 A EP95938351 A EP 95938351A EP 95938351 A EP95938351 A EP 95938351A EP 0748441 A1 EP0748441 A1 EP 0748441A1
Authority
EP
European Patent Office
Prior art keywords
layer
insulating layer
sensor element
sensor according
sealing ring
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.)
Withdrawn
Application number
EP95938351A
Other languages
German (de)
English (en)
Inventor
Karl-Hermann Friese
Frank Stanglmeier
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP0748441A1 publication Critical patent/EP0748441A1/fr
Withdrawn legal-status Critical Current

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
    • G01N27/4078—Means for sealing the sensor element in a housing
    • 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

Definitions

  • Electrochemical sensors are designed, for example, in the so-called finger design, in which the solid electrolyte body is tightly fixed as a closed tube in a metallic housing. With the finger probes, a distinction is made between the floating and the floating probes.
  • the conductor track of the outer electrode is contacted with the housing by means of an electrically conductive sealing ring. With the potential-free sensors, each electrode connection is fed directly to a control unit, so that no electrical contact with the housing is permitted. A seal between the solid electrolyte body and the housing must be implemented in both cases.
  • the solid electrolyte body and the conductor track are covered with an electrically insulating layer in the area of the sealing seat in the potential-free probe.
  • the sensor according to the invention with the characterizing features of the main claim has the advantage that the brittle, electrically insulating layer is protected from pressure peaks of the metallic sealing ring. This avoids the formation of cracks in the insulating layer, which would otherwise have a negative effect on the insulating effect and mechanical stability of the insulating layer. Due to the deformability of the covering layer, the sealing ring can press into the covering layer, so that a closed sealing seat is created.
  • the sensor according to the invention also leads to increased manufacturing reliability with regard to the gas tightness of the sensor element and improved durability with regard to
  • the material composition of the cover layer allows the use of commercially available substances or pastes and the use of known application techniques, such as screen printing technology.
  • FIG. 1 shows a longitudinal section through the exhaust-side part of a sensor according to the invention and FIGS. 2, 3 and 4 each show an enlarged section X according to FIG. 1.
  • the electrochemical sensor 10 shown in FIG. 1 has a metallic housing 11 which has a thread 13 on its outside as a fastening means for installation in a measuring gas tube, not shown.
  • the housing 11 has a longitudinal bore 18 with a sealing seat 19, which one metallic sealing ring 20 carries.
  • a sealing surface 22 on the sensor element side is formed on the bead-shaped head 15 of the sensor element 14 between the sealing ring 20 and the sensor element 14.
  • the sealing seat 19 in turn forms a sealing surface on the housing side.
  • the sensor element 14 has a tubular solid electrolyte body 23, the measuring gas-side end section of which is closed. On the outside exposed to the measuring gas there is a measuring electrode 25 on the solid electrolyte body 23 and one, a reference gas, e.g. Air exposed reference electrode 26 arranged.
  • the measuring electrode 25 is guided with a measuring electrode conductor track 27 to a first electrode contact 33 and the reference electrode 26 with a reference electrode conductor track 28 to a second electrode contact 34.
  • the electrode contacts 33, 34 are each located on one of the open ends of the
  • Solid electrolyte body 23 formed end face 36.
  • a por ⁇ rse protective layer 29 is placed over the measuring electrode 25.
  • Contact part 38 rests on the electrode contacts 33, 34.
  • the contact parts 38 are contacted with electrode connections 41.
  • the electrode connections 41 lead to a connection cable, not shown, which in turn leads to a measuring or control device.
  • a ceramic insulating sleeve 43 is also arranged in the longitudinal bore 18 of the housing 11. With the help of a mechanical means, not shown, the insulating sleeve 43 is pressed onto the contact parts 38.
  • the sensor element 14 protruding from the longitudinal bore 18 of the housing 1 on the measuring gas side is surrounded at a distance by a protective tube 44 which has openings 45 for the entry and exit of the measuring gas and at the end on the measuring gas side the housing 11 is held.
  • a rod-shaped heating element 40 is arranged in the interior of the sensor element 14, for example.
  • Sensor element 14 with an electrically conductive sealing ring 20 is that the electrodes 25, 26 or the conductor tracks 27, 28 and the solid electrolyte body are electrically insulated from the metallic housing 11.
  • the conductor track 27 is covered with an electrically insulating layer 21, in particular in the region of the sealing surface 22 on the sensor element side.
  • the insulating layer 21 has a layer thickness of, for example, 20 to 100 ⁇ m.
  • a ductile cover layer 31 is arranged above the insulating layer 21.
  • the layer thickness of the cover layer 31 should expediently be chosen so that at least the roughness depth of the insulating layer 21 is filled.
  • the layer thickness of the covering layer 31 preferably has 1.5 times the greatest roughness depth of the layer below.
  • the insulating layer 21 extends over the entire region of the conductor track 27, which is adjacent to the housing 11.
  • Cover layer 31 extends, for example, only slightly beyond the area of sealing ring 20. However, it is equally conceivable to restrict the insulating layer 21 to the area of the sealing ring 20 or the sealing surface 22, or to limit the insulating layer 21 on the measuring gas side
  • a second exemplary embodiment according to FIG. 3 consists in first coating the conductor track 27 with an intermediate layer 30, preferably made of the material of the solid electrolyte body, and laying the insulating layer 21 and the covering layer 31 over the intermediate layer 30 in accordance with the first exemplary embodiment already described, the intermediate layer 30 is expediently co-sintered.
  • the intermediate layer 30 has the function that the glass-forming material contained in the insulating layer 21 does not diffuse into the material of the conductor track 27 and there negatively influences the conductivity.
  • the insulating layer 21 consists of an electrically insulating ceramic material. Possible materials are: Al2O3, Mg spinel, fosterite or a mixture of these substances.
  • the insulating layer 21 consists of a mixture of a crystalline, non-metallic material and a glass-forming material, the insulating layer 21 being formed as a glaze filled with the crystalline, non-metallic material during sintering.
  • the specific electrical resistance of the crystalline, non-metallic material advantageously has at least 10 times the specific resistance of the solid electrolyte body 23.
  • the following can be used as the crystalline, non-metallic material: A1 2 0 3 , Mg spinel, fosterite, MgO-stabilized Zr ⁇ -> 2, CaO and / or Y2O3-stabilized ZrC> 2 with low stabilizer contents, advantageously with a maximum of 2/3 of the stabilizer oxide for full stabilization, non-stabilized Zr ⁇ 2 or Hf0 2 or a mixture of these substances.
  • the barium can be replaced by strontium up to 30 atomic percent.
  • the alkaline earth silicate glass can be used as premelted glass frit or introduced as a glass fiber raw material mixture, the latter being advantageously largely freed of water of crystallization, carbonate or other loss on ignition in a calcination process.
  • a small proportion ( ⁇ 10 percent by weight) of a glass-forming raw material mixture is advantageously added to the glass frit.
  • the material mixture may only contain electrically conductive impurities up to a maximum of 1 percent by weight, preferably less than 0.2 percent by weight.
  • the cover layer 31 is a ductile metal layer made of pure metals, such as, for example, palladium, copper, gold, nickel or the like, or of alloys which do not form any intermetallic phases, such as, for example, palladium / nickel, palladium / copper, copper / nickel or the like.
  • the metal layer 31 is deformable so that when the sensor element is inserted, the sealing ring 20 digs into the metal layer 31, as a result of which a closed sealing seat is created.
  • a particularly good bond between the cover layer 31 and the insulating layer 21 and the solid electrolyte body 23 is achieved by co-sintering the solid electrolyte body 23, the insulating layer 21 and the cover layer 31.
  • This embodiment lends itself to low melting metals, e.g. for copper or copper alloys.
  • the insulating layer 21 can also be applied subsequently to the sintered solid electrolyte body 23.
  • a third exemplary embodiment is shown in FIG. 4, in which a lower layer 32 is arranged under the cover layer 31 according to the exemplary embodiment in FIG.
  • the Bottom layer 32 is a dense ceramic layer, which preferably consists of the material of the solid electrolyte body 23, for example of stabilized Zr0 2 .
  • the flux content of the ceramic starting material is selected to be ⁇ 10%, with no addition of flux creating the densest layer.
  • the lower layer 32 itself does not have to have an insulation resistance, but rather can have a noticeable electron and / or ion conductivity. In the case of electrical conductivity, both the covering layer 31 and the lower layer 32 must not overlap the insulating layer 21.
  • the layer thickness of the lower layer 32 is expediently between 10 to 50 ⁇ m.
  • compositions and the production of the insulating layer 21 and the cover layer 31 are described below:
  • the raw materials are homogenized and ground in a ball mill with 90% Al2O3 grinding balls for two hours.
  • an aqueous slip is prepared with 50 g of raw material mixture, 500 ml of distilled water and 25 ml of 10% aqueous polyvinyl alcohol solution.
  • the slip is in one Ball mill ground with 90% Al 2 O3 grinding balls with a grinding time of 1.5 hours.
  • the slip is applied to the solid electrolyte body 23 and the conductor track 27 on the solid electrolyte body 23 presintered at 1000 ° C. from Zr0 2 partially stabilized with, for example, 5 mol% Y2O3, so that the insulating layer 21 according to FIG. 1 forms.
  • the slip is then dried at, for example, 60 ° C. Then a commercial paladium paste with 50
  • Weight percent Pd (purity 99.9%) with a layer thickness of 20 ⁇ m, for example, is applied over the insulating layer 21 in such a way that the cover layer 31 according to FIG. 1 forms. Subsequently, solid electrolyte body 23, insulating layer 21 and cover layer 31 are co-sintered for approximately 3 hours at 1450 ° to 1500 ° C.
  • the slip of the insulating layer 21 is applied to the solid electrolyte body 23 as described in Example 1.
  • the slip is dried in a forced air oven at, for example, 120 ° C. for about 1 hour.
  • the lower layer 32 according to FIG. 4 is applied from ZrO 2 stabilized with 5 mol% Y2O3.
  • Spray suspensions or printing pastes known per se are used in the prior art to produce the underlayer 32, the underlayer 32 being brushed on in the present example.
  • Sub-layer 32 is then dried at, for example, 60 ° C.
  • the cover layer 31 according to Example 1 is applied to the underlayer 32 and the
  • Solid electrolyte body 23 with the insulating layer 21, the lower layer 32 and the cover layer 31 co-sintered at 1450 ° to 1500 ° C. for about 3 hours.
  • the insulating layer 21 is produced as described in Example 1.
  • the insulating layer 21 will sintered together with the solid electrolyte body 23 at 1450 ° to 1500 ° C.
  • a copper paste with 60 weight percent copper with a layer thickness of 20 ⁇ m, for example, is applied as a covering layer 31.
  • the copper paste is sintered in a forming gas (90 N 2 / 10H 2), for example at 850 ° C.
  • the production of the insulating layer and the cover layer 31 follows as described in Example 3. However, a copper alloy paste of 98 volume percent copper and 2 volume percent titanium is used for the cover layer 31.
  • the copper alloy paste is sintered on in moist forming gas with a dew point of, for example, 25 ° C.
  • the copper alloy paste is sintered on at 850 ° C.
  • the layer system with the insulating layer 21 and the lower layer 32 is produced as described in Example 2.
  • the cover layer 31 is produced in accordance with the regulation described in Example 3.
  • Example 6 The production of the layer system with the insulating
  • Layer 21 and the lower layer 31 take place as described in Example 3.
  • a copper-palladium alloy paste with 50 percent by weight copper and 50 percent by weight paladium is used to produce the cover layer 31.
  • the copper / palladium alloy paste is sintered onto the sintered solid electrolyte body 23 at, for example, 900 ° C.
  • Example 7 The production of the layer system with the insulating
  • Layer 21 and the lower layer 32 take place as described in Example 3.
  • a Gold paste with, for example, 65 weight percent gold is used.
  • the gold paste is sintered onto the sintered solid electrolyte body 23 at, for example, 850 ° C. in air.
  • the layer system with the insulating layer 21 and the lower layer 32 is produced as described in Example 3.
  • a gold / copper alloy paste with 95 weight percent gold and 5 weight percent copper is used to produce the cover layer 31.
  • the subsequent sintering of the gold / copper alloy paste takes place at 820 ° C. in air, for example.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Molecular Biology (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Measuring Oxygen Concentration In Cells (AREA)

Abstract

La présente invention concerne une sonde électrochimique de mesure (10), destinée à la détermination de la teneur de mélanges gazeux en oxygène, en particulier les gaz d'échappement de moteurs à combustion interne. Cette sonde comprend un élément capteur (14) logé, de façon à être sans potentiel, dans une enveloppe métallique (11). L'élément capteur (14) possède un bloc d'électrolyte solide (23) conducteur des ions d'oxygène, qui a la forme d'un tube fermé d'un côté et pourvu d'électrodes (25, 26) et de bornes (27, 28) et il est mis en place dans l'enveloppe (11) avec une bague d'étanchéité métallique (20). La borne (27) qui se trouve à la surface extérieure du bloc d'électrolyte solide (23) est recouverte, tout au moins au voisinage de la bague d'étanchéité (20), d'une couche électriquement isolante (21). De plus, au voisinage de la bague d'étanchéité (20), une couche de recouvrement ductile (31) qui entoure le bloc d'électrolyte solide (23) est disposée par-dessus la couche isolante (21); l'élément capteur (14) repose sur la bague d'étanchéité (20) par son intermédiaire.
EP95938351A 1994-12-31 1995-11-28 Sonde electrochimique de mesure a element capteur sans potentiel Withdrawn EP0748441A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4447306A DE4447306A1 (de) 1994-12-31 1994-12-31 Elektrochemischer Meßfühler mit einem potentialfrei angeordneten Sensorelement
DE4447306 1994-12-31
PCT/DE1995/001684 WO1996021147A1 (fr) 1994-12-31 1995-11-28 Sonde electrochimique de mesure a element capteur sans potentiel

Publications (1)

Publication Number Publication Date
EP0748441A1 true EP0748441A1 (fr) 1996-12-18

Family

ID=6537533

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95938351A Withdrawn EP0748441A1 (fr) 1994-12-31 1995-11-28 Sonde electrochimique de mesure a element capteur sans potentiel

Country Status (5)

Country Link
US (1) US5690800A (fr)
EP (1) EP0748441A1 (fr)
JP (1) JPH09510298A (fr)
DE (1) DE4447306A1 (fr)
WO (1) WO1996021147A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1195602A1 (fr) 1997-11-20 2002-04-10 Denso Corporation Capteur d'oxygène, dans lequel l'élément chauffant contacte la surface intérieur du tube d'électrolyte solide, qui est fermé d'un côté

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19641808A1 (de) * 1996-10-10 1998-04-16 Bosch Gmbh Robert Dichtelement für Meßfühler und Verfahren zu seiner Herstellung
DE19641809C2 (de) * 1996-10-10 1998-07-30 Bosch Gmbh Robert Dichtelement für Meßfühler
JPH11153571A (ja) * 1997-11-20 1999-06-08 Denso Corp 酸素センサ素子
US6984298B2 (en) * 2002-01-09 2006-01-10 Delphi Technologies, Inc. Gas sensor having an insulating layer
DE10347796B4 (de) * 2003-10-14 2015-01-08 Robert Bosch Gmbh Messfühler zur Bestimmung der Konzentration einer Gaskomponente in einem Gasgemisch
DE102008005973B4 (de) * 2008-01-24 2014-04-03 Enotec Gmbh, Prozess- Und Umweltmesstechnik Verfahren zur Herstellung einer Messsonde und mit diesem Verfahren hergestellte Messsonde
JP2008286810A (ja) * 2008-08-25 2008-11-27 Denso Corp 酸素センサ素子
JP2008281584A (ja) * 2008-08-25 2008-11-20 Denso Corp 酸素センサ素子

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS60183857U (ja) * 1984-05-07 1985-12-06 株式会社デンソー 酸素濃度検出器
JP2708915B2 (ja) * 1989-11-25 1998-02-04 日本特殊陶業株式会社 ガス検出センサ
DE4318789A1 (de) * 1993-06-05 1994-12-08 Bosch Gmbh Robert Dichtung für ein Sensorelement eines Gassensors
DE4342731B4 (de) * 1993-07-27 2004-09-09 Robert Bosch Gmbh Elektrochemischer Meßfühler mit einem potentialfrei angeordneten Sensorelement und Verfahren zu seiner Herstellung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9621147A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1195602A1 (fr) 1997-11-20 2002-04-10 Denso Corporation Capteur d'oxygène, dans lequel l'élément chauffant contacte la surface intérieur du tube d'électrolyte solide, qui est fermé d'un côté

Also Published As

Publication number Publication date
DE4447306A1 (de) 1996-07-04
US5690800A (en) 1997-11-25
WO1996021147A1 (fr) 1996-07-11
JPH09510298A (ja) 1997-10-14

Similar Documents

Publication Publication Date Title
DE2913633C2 (de) Elektrochemischer Meßfühler für die Bestimmung des Sauerstoffgehaltes in Gasen, insbesondere in Abgasen von Verbrennungsmotoren sowie Verfahren zur Herstellung desselben
WO1995004273A1 (fr) Detecteur electrochimique pourvu d'un element de detection sans potentiel, et son procede de fabrication
DE19700700C2 (de) Sensorelement und Verfahren zu dessen Herstellung
DE102006035383A1 (de) Gasmessfühler und Herstellungsverfahren dafür
DE2657437B2 (de) Sauerstoff-Meßfühler
DE2908916C2 (de) Widerstandsmeßfühler zur Erfassung des Sauerstoffgehaltes in Gasen, insbesondere in Abgasen von Verbrennungsmotoren und Verfahren zur Herstellung derselben
DE3327991A1 (de) Gasmessfuehler
DE4342731B4 (de) Elektrochemischer Meßfühler mit einem potentialfrei angeordneten Sensorelement und Verfahren zu seiner Herstellung
DE4432749B4 (de) Sauerstoffkonzentrationsdetektor und Verfahren zu dessen Herstellung
DE19703636A1 (de) Luft/Kraftstoff-Verhältnissensor
WO2015193084A1 (fr) Élément détecteur pour détecter au moins une caractéristique d'un gaz à mesurer dans une chambre de gaz à mesurer
WO1996021147A1 (fr) Sonde electrochimique de mesure a element capteur sans potentiel
DE3628572C2 (fr)
DE3871686T2 (de) Elektrochemische zelle, mit integrierter struktur, zur messung der relativen konzentrationen von reaktiven stoffen.
DE19932545A1 (de) Heizleiter, insbesondere für einen Meßfühler, und ein Verfahren zur Herstellung des Heizleiters
DE4400370A1 (de) Elektrochemischer Meßfühler mit einem potentialfrei angeordneten Sensorelement
DE19545590C2 (de) Ko-gesinterte Cermet-Schicht auf einem Keramikkörper und ein Verfahren zu ihrer Herstellung
EP0683895B1 (fr) Systeme de couches isolantes permettant de separer des circuits par galvanisation
DE19526074C2 (de) Verfahren zur Herstellung einer gesinterten, elektrisch isolierenden keramischen Schicht
DE3934586C2 (fr)
DE19853601A1 (de) Verfahren zur Herstellung einer Isolationsschicht und Meßfühler
EP0741865B1 (fr) Element de detection
WO2002002993A1 (fr) Bougie crayon de prechauffage a detecteur de courant ionique et procede pour faire fonctionner une telle bougie
EP0487652B1 (fr) Capteur electrochimique
DE3735298C1 (de) Elektrochemischer Messfuehler

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17P Request for examination filed

Effective date: 19970113

17Q First examination report despatched

Effective date: 20020307

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20020601