| 摘要 |
PURPOSE:To improve durability and respondence, by employing heavier thickness, than other parts, for a porous protective coating, which is to be contacted by exhaust gas passing pores in a metallic protective tube, provided on a electrode layer on gas detecting side. CONSTITUTION:After forming electrodes 2 and 3 on the surface of a tube-like element 1 which is composed of a zirconia solid electrolyte and closed on one side, a powdery material composed of such a substance as MgAl2O4 is applied by plasma flame coating process onto the electrode 3 on the exhaust gas side to form a porous protective coating 4. And then, the element 1 is shielded by a shielding pipe having the same pore distribution as distribution of a pore 6 of a metallic protective pipe 5. The MgAl2O3 powder is shielded by the shielding pipe, and only the powder having passed the pore provided on the shielding pipe adheres to the formed porous protective coating 4, so that the portion to be directly contacted by the exhaust gas becomes thickner than other portions. |
