PRODUCTION OF PLATINUM RESISTOR

摘要

PURPOSE:To permit production of platinum resistor at low cost through a simplification of the pretreatment for plating, by employing a process having the steps of applying a platinum salt solution to a heat-resistant insulating ceramics substrate, firing the applied solution, plating the fired structure with platinum and then effecting a final firing. CONSTITUTION:A platinum salt solution is prepared by dissolving chloroplatinic acid in 2-butanol. The solution is applied to an alumina substrate 11 and is then fired. A non-electrolytic plating is effected at the room temperature on the fired laye with a plating liquid consisting mainly of an ammonia platinum complex to form a platinum layer. The platinum layer is then fired to become a platinum plating layer 12. A liquid formed by dispersing r-Al2O3, H2O in polyethylene glycol is applied to the central part of the platinum plating layer and is heated to become an alumina layer 13. A paste consisting of fine powder of rodium and polyethylene glycol is applied to the alumina layer 13 and is heated to become an oxide catalytic layer 14. The thus obtained structure can be used as a gas detector which exhibits small fluctuation of the characteristics.