Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
157 words
A device for detecting the concentration of oxygen in an automotive exhaust gas, comprising: an oxygen-ion-conductive solid electrolyte (11) positioned between a reference gas (A) and a gas (E) to be measured, the electrolyte generating an electromotive force proportional to a differential oxygen concentration between the two gases, and electrodes (12,13) made of an electroconductive material, a first one of the electrodes (13) being located on a surface of the oxygen-ion-conductive solid electrolyte (11) contacted by the reference gas (A) and a second one of the electrodes (12) being located on a surface of the solid electrolyte (11) contacted by the gas (E) to be measured, the surface of the electrode (12) in contact with the gas (E) to be measured being coated with a protective, heat-resistive metal oxide layer (14) having supported thereon uniformly a lead-trapping, thermally stable metal, the lead-trapping metal being present in a molar amount of 0.4 to 3% of said metal oxide.
Claim 2
Independent Claim
157 words
A device for detecting the concentration of oxygen in an automotive exhaust gas, comprising: an oxygen-ion-conductive solid electrolyte (11) positioned between a reference gas (A) and a gas (E) to be measured, the electrolyte generating an electromotive force proportional to a differential oxygen concentration between the two gases, and electrodes (12,13) made of an electroconductive material, a first one of the electrodes (13) being located on a surface of the oxygen-ion-conductive solid electrolyte (11) contacted by the reference gas (A) and a second one of the electrodes (12) being located on a surface of the solid electrolyte (11) contacted by the gas (E) to be measured, the surface of the electrode (12) in contact with the gas (E) to be measured being coated with a protective, heat-resistive metal oxide layer (14) having supported thereon uniformly a lead-trapping, thermally stable metal, the lead-trapping metal being present in a molar amount of 0.4 to 3% of said metal oxide.
Claim 3
Dependent Claim
25 words
A device according to claim 1, wherein the lead-trapping metal is selected from the group consisting of Pt, Ru, Pd, Ni, Au, and alloys thereof.
Claim 4
Dependent Claim
39 words
A device according to claim 1 or claim 2, wherein the protective layer is formed by first chemically plating or evaporating the lead-trapping metal onto the heat-resistive metal oxide, and then subjecting the thus-treated metal oxide to plasma spraying.
Claim 5
Independent Claim
25 words
A device according to any of claims 1 to 3, wherein the protective layer has a thickness in a range of 150 to 500 microns.