The present invention relates to an electrochemical sensor (10) intended to determine the gas contents in oxygen, including with regard to exhaust gas in internal combustion engines. It ressembles a solid electrolytic body (29) placed in a housing (11) with a sealing ring (21) consisting of a plurality of metal layers, the arrangement of which goes from a metal bearing (23) made of an alloy steel. The sealing ring (21) is covered on both sides with a roll-bonded copper layer (24), under which there can also be a nickel layer.
