US4296148A
Expired / Lapsed
US
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Method to apply multiple layers, including an electrode layer, on a sintered or pre-sintered ion conductive solid electrolyte body
Assignee: Robert Bosch GmbH
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Filing: 1979-11-29
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Granted: 1981-10-20
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Expires: 1999-11-29
Abstract
Abstract To improve response time and provide an electrode which has good adhesion to a solid electrolyte body, typically of zirconium, to be used in lambda sensors or polarographic current limit sensors, and additionally enhance the loading capability thereof, the pre-sintered or fully sintered solid electrolyte body, typically of zirconium dioxide, has an electrode layer applied thereto on which, in advance of sintering thereof, a cover layer is applied which, when sintered, develops pores. The cover layer is a ceramic material, sintered together with the electrode on the solid electrode body. This results in higher loading capability and decrease in response temperature to about 250 DEG C. The sensors can be used as lambda sensors and polarographic current sensors, to determine oxygen content in exhaust gases, typically for automotive engines, as well as in high-temperature fuel cells, high-temperature batteries, and high-temperature electrolysis cells.
Inventors
- 👤 Karl-Hermann Friese
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:33
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/407; G01N27/4075; B; B32; B32B; B32B18/00; C; C25; C25B; C25B9/00; C25B9/17; C25B9/19; C25B9/23; H; H01; H01M; H01M10/00; H01M10/36; H01M10/39; H01M10/3909; H01M10/3918; H01M10/3927; H01M4/00; H01M4/86; H01M4/88; H01M4/8878; H01M4/8882; H01M4/8885; H01M4/8889; H01M4/90; H01M4/9016; H01M4/9025; H01M4/9033; H01M4/9041; H01M4/905; H01M4/9058; H01M4/9066; H01M8/00; H01M8/10; H01M8/12; H01M8/1213; C04; C04B; C04B2235/00; C04B2235/65; C04B2235/656; C04B2235/6567; C04B2237/00; C04B2237/02; C04B2237/04; C04B2237/06; C04B2237/064; C04B2237/068; C04B2237/12; C04B2237/125; C04B2237/30; C04B2237/32; C04B2237/34; C04B2237/343; C04B2237/345; C04B2237/346; C04B2237/348; C04B2237/50; C04B2237/52; C04B2237/525; C04B2237/59; C04B2237/597; C04B2237/60; C04B2237/70; C04B2237/704; C04B2237/708; C04B2237/76; C04B2237/765; Y; Y02; Y02E; Y02E60/00; Y02E60/10; Y02E60/30; Y02E60/50; Y02P; Y02P70/00; Y02P70/50
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
256 words
Method of making a solid electrolyte ion conductive gas sensing element having a solid ion conductive electrolyte body (1) having two surface portions, one of which is adapted for exposure to the gas to be sensed a layer of electrode material (2) on one surface portion of the body; a layer of electrode material on the second surface portion of the body; a cover layer of porous ceramic material on the layer of electrode material on said one surface portion of the body; and a cover layer of porous ceramic material on the layer of electrode material on said second surface portion of the body, comprising the steps of providing a pre-sintered ion conductive solid electrolyte body having said two surface portions, applying a layer of the electrode material on one surface portion of said body; applying a layer of the electrode material on the second surface portion of said body; applying a cover layer of ceramic material which, when sintered, becomes porous, on the layer of electrode material on one surface portion of said body; applying a cover layer of ceramic material which, when sintered, becomes porous on the layer of electrode material on the second surface portion of said body; and then in one step, sintering the electrode layers and the cover layers, by heating the body with the electrode layers and the cover layers applied thereon to a temperature in which the sintering process of the electrode layers at least commences and the ion conductive body and the cover layer are completely sintered.
Claim 2
Dependent Claim
256 words
Method of making a solid electrolyte ion conductive gas sensing element having a solid ion conductive electrolyte body (1) having two surface portions, one of which is adapted for exposure to the gas to be sensed a layer of electrode material (2) on one surface portion of the body; a layer of electrode material on the second surface portion of the body; a cover layer of porous ceramic material on the layer of electrode material on said one surface portion of the body; and a cover layer of porous ceramic material on the layer of electrode material on said second surface portion of the body, comprising the steps of providing a pre-sintered ion conductive solid electrolyte body having said two surface portions, applying a layer of the electrode material on one surface portion of said body; applying a layer of the electrode material on the second surface portion of said body; applying a cover layer of ceramic material which, when sintered, becomes porous, on the layer of electrode material on one surface portion of said body; applying a cover layer of ceramic material which, when sintered, becomes porous on the layer of electrode material on the second surface portion of said body; and then in one step, sintering the electrode layers and the cover layers, by heating the body with the electrode layers and the cover layers applied thereon to a temperature in which the sintering process of the electrode layers at least commences and the ion conductive body and the cover layer are completely sintered.
Claim 3
Dependent Claim
72 words
Method according to claim 1, wherein the electrode layers comprise a paste including finely dispersed ceramic material and finely dispersed electrically conductive material; the paste is dried after applying the paste forming the electron conductive layer on the solid electrolyte body; and the cover layers are applied in the form of a ceramic slip, the composite of the ion conductive body with the paste and slip thereover applied thereto being sintered thereafter.
Claim 4
Dependent Claim
30 words
Method according to claim 2, wherein the volumetric relationship of the electrically conductive material to ceramic material in the paste which forms the electron conductive layers is above about 1:4.
Claim 5
Dependent Claim
41 words
Method according to claim 1, wherein the porous cover layers comprise at least one of the materials selected from the group consisting of: aluminum oxide, magnesium spinel, stabilized zirconium dioxide, pure zirconium dioxide, zirconium silicate, titanium dioxide, singly or in mixtures.
Claim 6
Dependent Claim
32 words
Method according to claim 4, wherein the material being applied over the electrode layers, before sintering, comprises a material which changes upon sintering by solid-state reaction to form the porous cover layers.
Claim 7
Dependent Claim
35 words
Method according to claim 5, wherein the material being applied to the electrode layers comprises a mixture of ZrO 2 and CaCO 3 to form, upon sintering, by solid-state reaction ZrO 2 stabilized by CaO.
Claim 8
Dependent Claim
37 words
Method according to claim 5, wherein the material being applied to the electrode layers comprises a mixture of: MgCO 3 and Al 2 O 3 to form, upon sintering by solid-state reaction, cover layers of magnesium spinel.
Claim 9
Dependent Claim
38 words
Method according to claim 4, wherein the material of the cover layers is a ceramic material which is in unstable form and which, during the subsequent sintering step, is transformed into the high temperature form by phase change.
Claim 10
Dependent Claim
55 words
Method according to claim 8, wherein the material applied to the electrode layers comprises at least one of the materials selected from the group consisting of: aluminum oxide in the form of γ--Al 2 O 3 , titanium dioxide in the form of anatas, or zirconium dioxide in the form of monocline ZrO 2 .
Claim 11
Dependent Claim
17 words
Method according to claim 4, including a pore-forming additive added to the material forming the cover layers.
Claim 12
Dependent Claim
26 words
Method according to claim 10, wherein the pore-forming additive comprises carbon black or ammonium carbonate, present in about 20% by volume or microspheres of organic materials.
Claim 13
Dependent Claim
28 words
Method according to claim 1, further comprising the step of applying further respective porous ceramic cover layers over said cover layers of ceramic material after the sintering step.
Claim 14
Dependent Claim
17 words
Method according to claim 12, wherein said further cover layers comprise magnesium spinel applied by plasma spraying.
Claim 15
Dependent Claim
17 words
Method according to claim 1, including the step of catalytically activating said cover layers of ceramic material.
Claim 16
Dependent Claim
18 words
Method according to claim 12, including the step of catalytically activating at least one of said cover layers.
Claim 17
Dependent Claim
43 words
Method according to claim 14, wherein the step of catalytically activating the respective cover layer comprises the step of adding a noble metal powder in a quantity of between about 0.1 to 10% (by volume) to the ceramic material forming the cover layer.
Claim 18
Dependent Claim
48 words
Method according to claim 15, wherein the step of catalytically activating the at least one cover layer comprises the step of adding a noble metal powder in a quantity of between about 0.1 to 10% (by volume) to the ceramic material forming said at least one cover layer.
Claim 19
Dependent Claim
55 words
Method according to claim 1, wherein the material of the layers of electrode material comprises a semiconductive ceramic material; and further including the step of heating said semiconductive ceramic material to a temperature below sintering temperature, then applying the cover layers of ceramic material and then conjointly sintering the electrode layers and the cover layer.
Claim 20
Dependent Claim
13 words
Method according to claim 18, wherein the semiconductive ceramic electrode material comprises Perovskite.
Claim 21
Dependent Claim
57 words
Method according to claim 1 or 2 or 3 or 10 wherein the pre-sintered ion conductive body comprises partially stabilized zirconium dioxide; and said single sintering step comprises heating the pre-sintered ion conductive solid electrolyte body with the electrode layers and the cover layers applied thereon to a temperature of between about 1,500° C. to 1,650° C.
Claim 22
Dependent Claim
53 words
Method according to claim 1, 2 or 3 or 10 wherein the presintered ion conductive body comprises fully stabilized zirconium dioxide; and the single sintering step comprises heating the presintered ion conductive solid electrolyte body, with the electrode layers and the cover layers applied thereon to a temperature of between about 1,400°-1,600° C.
Claim 23
Dependent Claim
57 words
Method according to claim 1, 2 or 3, or 10 wherein the presintered ion conductive body comprises zirconium dioxide, and the single sintering step comprises heating the presintered ion conductive solid electrolyte body, with the electrode layers and the cover layers applied thereon to a temperature of about 1,550° C. for a period of about 5 hours.
Claim 24
Dependent Claim
26 words
Method according to claim 21 wherein the single sintering step comprises heating for a period of about 1/2 hour to a temperature of about 1,500° C.
Claim 25
Dependent Claim
49 words
Method according to claim 1 wherein said single sintering step comprises heating the pre-sintered ion conductive solid electrolyte body with the electrode layers and the cover layers applied thereon to a temperature at which the electrode layers, the ion conductive body, and the cover layer are completely sintered together.
References Cited (Backward Citations)
US3347767A
Cited
US3503809A
Cited
US3645875A
Cited
US3978006A
Cited
US4021326A
Cited
US3843400A
Cited
US4005001A
Cited
US3935089A
Cited
US4096648A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-10-19 | 1985-04-20 | 1985-10-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-10-19 | 1989-04-20 | 1989-10-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-10-19 | 1993-04-20 | 1993-10-20 | $7700.00 | Window Closed / Lapsed |