SENSOR ELEMENT AND GAS SENSOR

摘要

A gas sensor includes a blocking portion 65 including an inner blocking layer 66 and outer blocking layer 67. The inner blocking layer 66 covers at least part of an exposed portion where solid-electrolyte layers are exposed as inner surfaces of a third internal cavity 61. The outer blocking layer 67 covers at least part of a nearest portion 6a that is at the shortest distance from the third internal cavity 61 among portions of outer surfaces of a multilayer structure where the solid-electrolyte layers are exposed. The inner blocking layer 66 and the outer blocking layer 67 do not each conduct one or more kinds of substances that contain oxygen. The outer blocking layer 67 covers the entirety of the nearest portion 6a. An area ratio A/B of a covered area A by which the blocking portion 65 covers the solid-electrolyte layers to an exposed area B by which the solid-electrolyte layers are exposed as the inner surfaces of the third internal cavity 61 is 0.3 or greater.