| 摘要 |
PURPOSE:To prevent conduction between electrodes by removing carbon accumulated with a catalytic reaction through a catalyst layer provided at the end of a retaining body. CONSTITUTION:A pair of electrodes 2a made of platinum or the like are buried in a detecting element 1 made up of a metal oxide sintered body. The electrodes 2a of the detecting element 1 are inserted into a through hole 3a of a cylindrical ceramic body 3 and connected to a sublead wire 2b. The ceramic body 3 is provided on side of the detecting element with a groove 3b for retaining the detecting element 1 and a groove 3c which allows exhaust gas to run to the detecting element 1. A caralyst layer 3d is provided like a belt along the grooves 3b and 3c passing through the center of the one pair of through holes 3a. A slurry mainly composed of an alumina containing about 5wt% of platinum, palladium, rhodium or the like is applied as this catalyst metal and baked at about 1,000 deg.C. With such an arrangement, carbon accumulated between the electrodes can be purified and removed by a catalytic reaction thereby enabling accurate measurement of the resistance of the detecting element. |
