| 摘要 |
PURPOSE:To avert the deformation and closing of a gas diffusion hole even in an atmosphere contg. corrosive gases or gaseous fluorocarbon, etc., and to allow the execution of the measurement of an oxygen concn. stably over a long period of time by providing corrosion resistant material layers which cover at least the wall surface of the gas diffusion hole of a housing. CONSTITUTION:An anode electrode 2 and a cathode electrode 3 are formed on both sides of a solid electrolyte base plate 1. The internal space enclosed by the surface of the base plate 1 on the electrode 3 side and the inside surface of a cap 5 is formed. This internal space is communicated with the outside by the gas diffusion hole 6 bored in the cap 5. The corrosion resistant material layers 7 consisting of platinum or gold are formed on the wall surface of the diffusion hole 6 and the region, near the diffusion hole 6, of the outside and inside surfaces of the cap 5. The generation of reaction products in and near the diffusion hole 6 is, therefore, averted even if this sensor is used in the atmosphere contg. the corrosive gases. The oxygen concn. is stably measured even in the atmosphere contg. the corrosive gases in this way without allowing the diffusion hole 6 to be closed or reduced in diameter by the reaction products. |
