| 摘要 |
PURPOSE:To detect oxygen concns. from a low region up to a high region by providing a porous inorg. coating layer on the cathode surface of a threshold electric current type oxygen sensor. CONSTITUTION:Metallic electrodes 2, 3 are provided by a sputtering method on both surfaces of a solid electrolyte sintered body 1 formed in a disc shape. Lead wires 6, 6 for the purpose of voltage application and output detection are provided on the electrodes 2, 3. A porous inorg. coating layer 5 for limiting oxygen inflow is provided thickly or densely on the surface of the electrode (cathode) 2 on the oxygen inflow side and a thin porous inorg. electrode protecting layer 5 is provided on the surface of the electrode (anode) 3 on the oxygen outflow side. The electrodes 2, 3 formed to the sensor element consist of a mixture of a component selected from platinum and gold having heat resistance, oxidation resistance and good electric conductivity, and a component selected from silver, palladium and rhodium making compounds unstable with oxygen. |
