| 摘要 |
PURPOSE:To make it possible to measure the air/fuel ratio in a rich region with high reliability, by extending and forming inner and outer electrodes at two recess parts of the end surface of a detecting element, bonding signal lead- out metal members to the electrodes, and coating the junctions. CONSTITUTION:A detecting element 13 comprises zirconia electrolyte 23 having two recess parts at the opening end part of a bag-tube type element. Porous platinum is formed on the facing inner and outer surfaces as electrodes by plating. Inner and outer electrodes 21 and 22 are extended and formed to the opening end surface of the element. A diffused resistor which determines the rate of gas diffusion is formed on the electrode 22 by plasma flame coating and the like. Relay leads 8a and 8b comprises soft Ni wire. The head parts of the leads has a nail shape and comprise metal members. The leads are used for leading a signal out of the element 13. The leads 8a and 8b are metallized and bonded to the electrodes 21 and 22 at two recess parts by baking of platinum paste. The recess parts are coated, sealed and protected with glass 9. Corrosion of the metallized junction due to moisture and the like intruded through an atmosphere introducing port is prevented by said sealing. Furthermore, heat resistance and tensile strength can be improved. |
