| 摘要 |
PURPOSE:To achieve stability and high accuracy in sensor output by selectively forming Na2CO3 at the edge part of the contact surface between an anode electrode and Na<+> conductive solid electrolyte and only at the outer part in contact with gas to be detected. CONSTITUTION:A cathode electrode is formed at one end part of an Na<+> conductive solid electrolyte 1, and an anode electrode is formed at the other end. Since the anode electrode 4 is porous, many communicating holes 4b reaching a surface 1a of the electrolyte 1 are present. A current is conducted with the anode electrode as the (-) electrode and with the cathode as the (+) electrode in the electrolyte 1 under the temperature at which Na<+> conductivity is displayed under the atmosphere containing carbon dioxide gas and oxygen. Then, reaction occurs between the oxygen and the carbon dioxide gas which are diffused through the communicating holes 4b at an edge part 5 of the contact surface. Thus, Na2CO3 is formed. Since the Na2CO3 are arranged at the outer part 5 in contact with gas to be detected, the electromotive force which is proportional to the concentration of the carbon dioxide gas is generated across the electrodes. |
