| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas sensor element which can detect an excess air ratio on the rich side, a gas sensor using the same, and an exhaust gas purification device using the gas sensor.SOLUTION: A gas sensor element 1 comprises: a solid electrolyte 2 having oxide ion conductivity; a measured gas side electrode 3 arranged on one surface of the solid electrolyte 2 to be brought into contact with measured gas; and a reference gas side electrode 4 arranged on the other surface of the solid electrolyte 2 to be brought into contact with reference gas. On a surface 300 of the measured gas side electrode 3, an electrode covering part 5 formed of a compound containing at least one or more kinds of elements selected from Ba, Sr, Cs, Rb, K, Na and La is formed intermittently over the surface 300 of the measured gas side electrode 300. The compound constituting the electrode covering part 5 exists without being chemically combined with an electrode material constituting the measured gas side electrode 3. |
