| 摘要 |
PURPOSE:To obtain the sensor which is free from deterioration of the initial characteristics and durability and has stable characteristics by constituting the protective layer of an electrode of a multilayer structure which becomes a layer of small particle size as it is provided toward the inside. CONSTITUTION:The protective layers 24, 25, 26 having the same thickness are provided in order on the outside electrode 23 consisting of a platinum catalytic layer in a zirconia tube 22. Particle size is made smaller as the layer is provided in the inside. Therefore a thermally-sprayed low material is comparted into three classes having prescribed particle size by a classifier. The outside electrode is coated with the protective layers in order from the first layer 24 having small particle size by plasma coating. Since the third layer 26 has large particle size, gas and impurities are passed through it. Gas is properly squeezed by the first layer 24 having small particle size and the impurities are not trapped. Thereby the initial characteristics and durability are stabilized. |
