ELECTROCHEMICAL MEASUREMENT SENSOR WITH A POTENTIAL-FREE SENSOR ELEMENT AND PROCESS FOR PRODUCING THE SAME

摘要

An electrochemical measurement sensor (10) for determining the oxygen content of gasses, in particular the oxygen content of exhaust gas from internal combustion engines, has a potential-free sensor element (14) with an oxygen ion-conductive solid electrolyte body (23) shaped as a pipe closed at one end. The solid electrolyte body (23) has on its outer surface an outer electrode (25) with a conductor strip (27) at the connection side which also extends on the outer surface, and is set into a metallic housing (11) with a sealing ring (20). The sensor element (14) has at least in the area of the sealing ring (20) an electrically insulating layer (21) which covers at least the conductor strip (27) towards the housing (11). The insulating layer (21) is made of a mixture of a crystalline, non-metallic material and of a vitrifying material. During manufacture, the insulating layer (21) is subjected to a thermal treatment at a temperature above the melting point of the vitrifying material, so that the insulating layer (21) forms a glaze filled with the crystalline, non-metallic material.