| 摘要 |
PROBLEM TO BE SOLVED: To obtain an air/fuel ratio sensor element that incorporates an electrical heating element, and at the same time has improved durability also against thermal shock properties such as rapid temperature increase. SOLUTION: Inner and outer electrodes 3 and 4 are formed at positions where the inner and outer surfaces of a cylindrical pipe 2 that is made of solid electrolyte having oxygen ion conductivity and whose one end is sealed oppose each other, A space Section 5 for exposing one portion or entire portion of the external electrode 4 is provided on the outer surface of the cylindrical pipe 2. A ceramic layer 7 where an electrical heating element 6 is buried is formed around the space section 5. A solid electrolyte layer 8 having oxygen ion conductivity is provided so that the space section 5 is blocked. Then, a diffusion hole 11 for taking in gas to be measured in the blocked space section 5 is formed on the solid electrolyte layer 8. |
