Patent ID: 11921078
Assignee: NGK INSULATORS, LTD.
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A sensor element that detects a specific gas concentration in a measurement-object gas, the sensor element comprising:
an element body including an oxygen-ion-conductive solid electrolyte body, the element body having a measurement-object gas flow section formed therein, the measurement-object gas flow section through which a measurement-object gas is introduced and flows;
a measurement electrode disposed on an inner peripheral surface of the measurement-object gas flow section;
a reference electrode disposed in the element body, the reference electrode being exposed to a reference gas used as a reference for detecting the specific gas concentration; and
a porous protective layer arranged to cover a part of a surface of the element body,
wherein the protective layer includes an inlet protective layer arranged to cover a gas inlet formed in the surface of the element body, the gas inlet being an inlet of the measurement-object gas flow section, and at least a part of a face included in the surface of the element body, the face on which the gas inlet is opens,
wherein the inlet protective layer has an internal space formed therein, and
wherein an arithmetic average roughness Rap of an inner peripheral surface of the internal space of the inlet protective layer satisfies at least one of conditions below: the arithmetic average roughness Rap is 8 μm or more, and the arithmetic average roughness Rap is higher than an arithmetic average roughness Rac of a bonding surface of the protective layer, the bonding surface at which the protective layer is bonded to the element body.