| 摘要 |
PROBLEM TO BE SOLVED: To provide a gas sensor element of high durability which prevents a solution containing a poisoning substance adhered to a measurement electrode protective layer from reaching at the inside of the pores of a measurement electrode and being suppressed from the lowering of sensitivity, produced by the deterioration in the measurement electrode and the closure of the pores of the measurement electrode caused by the poisoning substance.SOLUTION: The gas sensor element 100 includes a base member 101 comprising a plurality of laminating solid electrolyte layers and having a space that communicates with the outside of the gas sensor element and allows introduction of the gas to be measured into the gas sensor element, and a porous measurement electrode 44 that is formed on a surface of the space inside the base member 101, and is covered with a porous measurement electrode protection layer 45, wherein an average pore size A of the measurement electrode 44 and an average pore size B of the measurement electrode protective layer 45 satisfy the relationship: 0.05≤B/A≤0.9; the measurement electrode 44 has an average pore size of 0.5-15 μm, and the measurement electrode protecting layer 45 has an average pore size of 0.05-9 μm, a porosity of 5-50%, and a thickness of 10-200 μm. |
