Electrochemical sensor with a potential-free arranged sensor element and method for its preparation

An electrochemical sensor for determining the oxygen content of gases, in particular for determining the oxygen content in exhaust gases of internal combustion engines, with a potential-free arranged sensor element having an oxygen ion conductive solid electrolyte body, preferably in the form of a unilaterally closed tube, and electrodes having electrically conductive terminals, wherein the sensor element with a sealing ring is inserted in a metallic housing and at least a housing supplied opposite, electrically conductive connection by means of an electrically insulating layer in the region of the sealing ring relative to the housing is electrically insulated, characterized in that the insulating layer (27) consists of a mixture of a crystalline, is formed non-metallic material and a glass forming material, such that upon heating a filled with the crystalline, non-metallic material glaze forms.