OXYGEN SENSOR AND MANUFACTURE THEREOF

摘要

PURPOSE:To inhibit lead poisoning, by forming a layer made of one or both of rhodium and palladium on the surface of a first electrode in a sensor in which the first electrode made of platinum is provided on the side facing a gas to be measured of a solid electrolyte while a second electrode on the opposite side thereof. CONSTITUTION:A first electrode 21 is formed on the side facing a gas to be measured of a solid electrolyte 1 in which an oxide of yttrium or the like is added to zirconium while a second electrode 22 on the opposite side thereof. The first electrode 21 is made up of a layer comprising one or both of rhodium and palladium with the thickness of 10-5,000Angstrom and a protective layer 3 on a platinum layer about 0.1-1.5mum thick. The second electrode 22 can use precious metal such as palladium, preferably platinum. Then, these electrodes are held with a holder 4 having a spring 6 and a lead 5 and mounted on a flange 7. This can inhibit lead poisoning thereby enabling a long-time use without lowering the response.