Gas sensor element, method for manufacturing the same, and gas sensor

A gas sensor element comprising:

• a solid electrolyte member having a plate-like shape;
• an electrode formed on the solid electrolyte member;
• and
• a protection layer including a reinforcement member having an insertion hole, and a porous electrode protection member provided in the insertion hole and adapted to protect the electrode from becoming poisoned;
• wherein a gap in excess of an average diameter of pores in the electrode protection member is absent between an inner peripheral surface of the insertion hole and an outer peripheral surface of the electrode protection member.

A gas sensor comprising a gas sensor element for detecting a gas to be measured, and a metallic shell for supporting the gas sensor element,

• wherein the gas sensor element comprises:
• a solid electrolyte member having a plate-like shape;
• an electrode formed on the solid electrolyte member;
• and
• a protection layer including a reinforcement member having an insertion hole, and a porous electrode protection member provided in the insertion hole and adapted to protect the electrode from becoming poisoned;
• and
• a gap in excess of an average diameter of pores in the electrode protection member is absent between an inner peripheral surface of the insertion hole and an outer peripheral surface of the electrode protection member.

A method for manufacturing a gas sensor element comprising a solid electrolyte member having a plate-like shape, an electrode formed on the solid electrolyte member, and a protection layer including a reinforcement member having an insertion hole, and a porous electrode protection member provided in the insertion hole and adapted to protect the electrode from becoming poisoned,

• the method comprising:
• punching the insertion hole in a first green ceramic sheet so as to form a green reinforcement member having the insertion hole;
• blanking out a blank from a second green ceramic sheet placed on the green reinforcement member so as to dispose the blank as a green electrode protection member in the insertion hole of the green reinforcement member;
• and
• firing the green reinforcement member and the green electrode protection member so as to form the reinforcement member and the electrode protection member.