EP0064666A1
Expired / Lapsed
EP
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Method of producing ceramic substrate having heater layer formed by using conductive paste
Assignee: Nissan Motor Co Ltd
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Filing: 1982-04-27
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Granted: —
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Expires: 2002-04-27
Abstract
Abstract method of producing a ceramic substrate (28), which has a thin heater layer (34) and is useful in a gas sensing element (30) such as a solid electrolyte oxygen sensing element of the concentration cell type, through the steps of applying a paste containing a conductive powder which comprises a metal of the platinum group onto a sheet (12) of an unfired ceramic material so as to form a conductive paste layer (14) in the pattern of an intended heater layer, drying the paste layer (14) and sintering the ceramic material sheet (12) and the conductive powder container in the paste layer (14) simultaneously. As the improvement, the conductive powder in the paste is required to be not greater than 10.0 m 2 /g in specific surface area. This limitation has the effect of enhancing the stability and durability of the heater layer (34) even when the substrate (28) is subjected to severe conditions as in exhaust systems in automobiles.
Inventors
- 👤 Yoshio c/o Oppama Plant of Akimune
- 👤 Satoshi c/o Oppama Plant of Ambe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 23:00
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/26; G01N27/403; G01N27/406; G01N27/407; G01N27/4071; G01N27/02; G01N27/04; G01N27/12; G01N27/4067
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
152 words
A method of producing a ceramic substrate which has a heater layer and is useful in a gas sensing element, the method having the steps of applying a paste containing an electrically conductive powder, which comprises a metal selected from metals of the platinum group and alloys thereof dispersed in an organic liquid vehicle, onto an unfired sheet (12) formed of a composition containing a powder of a ceramic materail so as to form a conductive paste layer (14) in the pattern of an intended heater layer (34), drying the conductive paste layer, and firing said sheet on which the conductive paste layer is formed so as to sinter the conductive paste layer into a solid heater layer (34) and to simultaneously sinter said sheet into a rigid ceramic substrate (28), characterized in that said conductive powder in said paste is not greater than 10.0 m 2 /g in specific surface area.
Claim 2
Independent Claim
152 words
A method of producing a ceramic substrate which has a heater layer and is useful in a gas sensing element, the method having the steps of applying a paste containing an electrically conductive powder, which comprises a metal selected from metals of the platinum group and alloys thereof dispersed in an organic liquid vehicle, onto an unfired sheet (12) formed of a composition containing a powder of a ceramic materail so as to form a conductive paste layer (14) in the pattern of an intended heater layer (34), drying the conductive paste layer, and firing said sheet on which the conductive paste layer is formed so as to sinter the conductive paste layer into a solid heater layer (34) and to simultaneously sinter said sheet into a rigid ceramic substrate (28), characterized in that said conductive powder in said paste is not greater than 10.0 m 2 /g in specific surface area.
Claim 3
Dependent Claim
27 words
A method according to Claim 1, wherein said conductive powder is entirely a powder of a metal selected from metals of the platinum group and alloys thereof.
Claim 4
Dependent Claim
44 words
A method according to Claim 1, wherein said conductive powder is a mixture of a major amount of a powder of a metal selected from metals of the platinum group and alloys thereof and a minor amount of a powder of a ceramic material.
Claim 5
Dependent Claim
30 words
A method according to Claim 1, wherein the specific surface area of said conductive powder is in the range from 0.1 to 5 . 0 m 2 / g .
Claim 6
Dependent Claim
49 words
A method according to Claim 1, further comprising the step of placing end portions of two lead wires on said unfired sheet after the step of applying said paste such that tip portions of said two lead wires lie on two terminal regions of said conductive paste layer, respectively.
Claim 7
Dependent Claim
52 words
A method according to Claim 1 or 5, further comprising the step of placing another unfired sheet (16) formed of said composition on said sheet (12) after the application of said paste but before the sintering step such that said conductive paste layer is sandwiched between said sheet and said another sheet.
Claim 8
Dependent Claim
25 words
A method according to Claim 1, wherein said organic liquid vehicle comprises a cellulose derivative which serves as a binder dissolved in an organic solvent.
Claim 9
Dependent Claim
22 words
A method according to Claim 1, wherein said ceramic material is selected from the group consisting of alumina, mullite, spinel and forsterite.
Claim 10
Dependent Claim
18 words
A method according to Claim 1, wherein said paste is applied to said sheet by a screen-printing method.
References Cited (Backward Citations)
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