SENSOR ELEMENT FOR DETERMINING GAS ELEMENT CONCENTRATION IN MIXED GAS, AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To provide a sensor element 10 equipped with a pump cell which has 1st and 2nd electrodes 20, 23 for detecting gas element concentration of mixed gas, wherein the 1st electrode is arranged in a measuring gas chamber 13 of the sensor element, while the pump cell is pumping the oxygen inside and outside the measuring gas chamber of the sensor element, so as to inhibit generation of λ=1 fluctuation property and also overcome any fault involved in it when composition of the mixed gas dynamically varies. SOLUTION: In this sensor element, the 2nd electrode is larger than the 1st electrode in face flare, which has a diffusion barrier 26 for the mixed gas diffusing toward the 2nd electrode itself to specify diffused resistance depending on porosity level and/or thickness of the diffusion barrier. As a result, the specific impressed pumping voltage is selected so that the same pumping current as the one which ought to be generated when both the electrodes have the same face flare in magnitude being exposed to the mixed gas may flow between the electrodes. COPYRIGHT: (C)2006,JPO&NCIPI