Electrically conductive oxide sintered compact, member for electrical conduction, gas sensor, piezoelectric element, and method for producing piezoelectric element

Patent metadata

Field	Value
Publication number	US-10629322-B2
Application number	US-201515528991-A
Country	US
Kind code	B2
Filing date	Dec 7, 2015
Priority date	Dec 15, 2014
Publication date	Apr 21, 2020
Grant date	Apr 21, 2020

Abstract

An electrically conductive oxide sintered compact according to one embodiment of the present invention includes a crystal phase that has a perovskite oxide crystal structure represented by the composition formula: REaCobCucNidOx where RE is a rare-earth element; a+b+c+d=1; and 1.25≤x≤1.75, wherein the values of a, b, c and d respectively satisfy the following conditions: 0.474≤a≤0.512; 0.050≤b≤0.350; 0≤c≤0.250; and 0.050≤d≤0.350.

First claim

The invention claimed is:

1. An electrically conductive oxide sintered compact comprising a crystal phase that has a perovskite oxide crystal structure represented by the composition formula: RE a Co b Cu c Ni d O x where RE is a rare-earth element selected from the group consisting of La, Pr, Nd, Pm and Sm; a+b+c+d=1; and 1.25≤x≤1.75, wherein the values of a, b, c and d respectively satisfy the following conditions:
0.487≤ a≤ 0.506;

0.050≤ b≤ 0.250;

0.098< c< 0.250; and
0.244≤ d≤ 0.275.

2. The electrically conductive oxide sintered compact according to claim 1 , wherein the rare-earth element RE is La.

3. An electrical conduction member, comprising:
a substrate formed of a ceramic material; and
a conductor layer formed of the electrically conductive oxide sintered compact according to claim 1 on a surface of the substrate.

4. A gas sensor comprising an electrode formed of the electrically conductive oxide sintered compact according to claim 1 .

5. A piezoelectric element, comprising:
a piezoelectric ceramic body formed of a piezoelectric ceramic composition; and
an electrode formed of the electrically conductive oxide sintered compact according to claim 1 on a surface of the piezoelectric ceramic body.

6. A method for producing the piezoelectric element according to claim 5 , comprising:
a forming step of forming a green compact of the piezoelectric ceramic composition;
a first firing step of firing the green compact at a first firing temperature, thereby providing the piezoelectric ceramic body;
an application step of applying a conductive oxide paste for formation of the electrically conductive sintered compact to the surface of the piezoelectric ceramic body; and
a second firing step of firing the piezoelectric ceramic body with the conductive oxide paste applied thereto at a second firing temperature lower than the first firing temperature.

Assignees

• Ngk Spark Plug Co

Inventors

• Kozuka Hisashi
• Okimura Yasuyuki
• Ohbayashi Kazushige

Classifications

• G01N2291/0426

  Bulk waves, e.g. quartz crystal microbalance, torsional waves · CPC title

• G01N29/022

  Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices (microdevices per se B81B) · CPC title

• C04B2235/762

  Cubic symmetry, e.g. beta-SiC · CPC title

• G01N2291/0256

  Adsorption, desorption, surface mass change, e.g. on biosensors · CPC title

• C04B2235/3203

  Lithium oxide or oxide-forming salts thereof · CPC title