| 摘要 |
An oxygen concentration detector 90 includes a one-end closed cylindrical oxygen sensing element 91 having an inside electrode 32, outside electrode 31 provided on the inner side and outer side respectively, an electrode protecting layer 2 made up of ceramics porous member provided further outside the outside electrode, and a trap layer 1 of ceramics porous member having a surface roughness of 20 to 100 mu m measured according to a 10 point mean roughness measurement and provided outside the electrode protecting layer 2 is employed. By dipping the to-be-detected gas side surface of an oxygen sensing element into a slurry with coarse heat-resisting metal oxide particles, 2 to 50 mu m in average grain size, dispersed, depositing the slurry on the surface of a protective layer of an oxygen sensor element, thereafter drying and baking the deposit, a porous poisonous substance trap layer, 10 to 500 mu m thick, is formed. The dipping is performed after a previous degassing and strong stirring of said slurry and the stop of stirring. <IMAGE> |
