Gas sensor element and gas sensor

Patent metadata

Field	Value
Publication number	US-10012612-B2
Application number	US-201615207690-A
Country	US
Kind code	B2
Filing date	Jul 12, 2016
Priority date	Jul 13, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

An inside lead portion of a gas sensor element has a lanthanum zirconate layer arranged between an electrically conductive oxide layer and a solid electrolyte member. Meanwhile, an inside detection electrode portion of the gas sensor element is formed such that (i) no lanthanum zirconate layer is formed between an electrically conductive oxide layer and the solid electrolyte member, or (ii) a lanthanum zirconate layer thinner than the lanthanum zirconate layer of the inside lead portion is formed between the electrically conductive oxide layer and the solid electrolyte member.

First claim

What is claimed is:

1. A gas sensor element comprising:
a solid electrolyte member extending in an axial direction and containing ZrO 2 having oxygen-ion conductivity;
an outside electrode provided on one of surfaces of the solid electrolyte member and which comes into contact with a gas under measurement; and
an inside electrode provided on an opposing surface of the solid electrolyte member and which comes into contact with a reference gas,
the inside electrode including an inside detection electrode portion disposed on a forward end side in the axial direction and which detects a particular gas contained in the gas under measurement, and an inside lead portion which is disposed rearward of the inside detection electrode portion, which is connected to the inside detection electrode portion, and which comes into contact with a connection terminal for external output, wherein
the inside electrode includes an electrically conductive oxide layer whose main component is a perovskite phase which is represented by a composition formula of La a M b Ni c O x (where M is at least one element selected from Co and Fe, a+b+c=1, 1.25≤x≤1.75) and has a perovskite-type crystal structure;
the coefficients a, b, and c satisfy 0.459≤a≤0.535, 0.200≤b≤0.475, and 0.025≤c≤0.350;
the inside lead portion includes a lanthanum zirconate layer between the electrically conductive oxide layer and the solid electrolyte member; and
the inside detection electrode portion is formed such that (i) no lanthanum zirconate layer is formed between the electrically conductive oxide layer and the solid electrolyte member, or (ii) a lanthanum zirconate layer formed between the electrically conductive oxide layer and the solid electrolyte member is thinner than the lanthanum zirconate layer of the inside lead portion.

2. The gas sensor element as claimed in claim 1 , wherein a reaction prevention layer containing a rare earth element-added ceria as a main component is provided between the inside detection electrode portion and the solid electrolyte member.

3. The gas sensor element as claimed in claim 2 , wherein the reaction prevention layer is provided only on the forward end side of the gas sensor element with respect to a holding member which holds the gas sensor element when the gas sensor element is incorporated into a gas sensor.

4. The gas sensor element as claimed in claim 1 , wherein
the inside detection electrode portion has an intermediate electrically conductive layer formed between the reaction prevention layer and the electrically conductive oxide layer,
the electrically conductive oxide layer contains no rare earth element-added ceria and comprises a perovskite phase represented by the composition formula La a M b Ni c O x , and
the intermediate electrically conductive layer comprises a perovskite phase represented by the composition formula La a M b Ni c O x and a rare earth element-added ceria.

5. The gas sensor element as claimed in claim 1 , wherein
the electrically conductive oxide layer contains a first electrically conductive oxide layer which constitutes the inside lead portion and a second electrically conductive oxide layer which constitutes the inside detection electrode portion,
each of the first electrically conductive oxide layer and the second electrically conductive oxide layer contains the perovskite phase and a rare earth element-added ceria, and
the proportion of the rare earth element-added ceria in the second electrically conductive oxide layer is equal to or greater than the proportion of the rare earth element-added ceria in the first electrically conductive oxide layer.

6. A gas sensor comprising:
the gas sensor element as claimed in claim 1 ; and
a holding member for holding the gas sensor element.

Assignees

• Ngk Spark Plug Co

Inventors

• Ohtsuka Shigehiro
• Nishi Tomohiro
• Nakagawa Keisuke
• Ito Kazuma
• Kato Ippei

Classifications

• G01N27/419

  Measuring voltages or currents with a combination of oxygen pumping cells and oxygen concentration cells · CPC title

• G01N27/00 Primary

  Investigating or analysing materials by the use of electric, electrochemical, or magnetic means (G01N3/00 – G01N25/00 take precedence; measurement or testing of electric or magnetic variables or of electric or magnetic properties of materials G01R) · CPC title

• G01N27/4076 Primary

  Reference electrodes or reference mixtures · CPC title

• G01N27/4073

  Composition or fabrication of the solid electrolyte · CPC title

• G01D11/30

  Supports specially adapted for an instrument; Supports specially adapted for a set of instruments · CPC title