| 摘要 |
PURPOSE:To enhance the durability of an exhaust gas sensor by forming a porous lead sticking layer which captures particulate lead components and deposits the same thereon within a porous protective layer formed to cover a platinum electrode on a discharge passage side. CONSTITUTION:The lead sticking layer 14 for capturing the fine lead particles contained in an exhaust gas and sticking and depositing the same thereon is formed in the protective layer 8. This layer 14 is formed by using platinum Pt, etc., like a platinum electrode 4b. A compact sintered body is used for a solid electrolyte 2. For example, the electrolyte is formed by using ZrO2 added with a small amt. of Y2O3 as a base material, molding this material to a bottomed cylindrical shaped cup-like body and calcining the molding. The paste of platinum is coated on the inside and outside peripheral faces of the solid electrolyte 2 and is calcined to form the porous platinum electrodes 4a, 4b having about 5-10mum thickness. MgA1204 or the like is then thermally sprayed by plasma onto the surface of the electrode 4b to form the protective layer 8a. The electrolyte is then immersed in a chloroplatinic acid soln. contg. platinum and is calcined to form the lead sticking layer 14 consisting of the platinum; further, MgA1204 or the like is thermally sprayed on the surface of the protective layer 8a to form the 2nd protective layer 8b, by which the sensor element part is obtd. |
