Piezoelectric material, piezoelectric member, piezoelectric element, and pressure sensor

Patent metadata

Field	Value
Publication number	US-9522827-B2
Application number	US-201313875853-A
Country	US
Kind code	B2
Filing date	May 2, 2013
Priority date	May 2, 2013
Publication date	Dec 20, 2016
Grant date	Dec 20, 2016

Abstract

The present invention has an object to provide a piezoelectric material that endures high temperatures, the resources of raw materials of which are abundant, and that is stably suppliable. Disclosed is a piezoelectric element, including: a piezoelectric member having a surface for receiving external stress and a side surface that is perpendicular to the surface for receiving external stress; and at least one pair of a first electrode and a second electrode that are placed on the side surface, the first electrode being provided so as to separate from the second electrode. The piezoelectric member is preferably cut out from a piezoelectric material that includes gehlenite (Ca 2 Al 2 SiO 7 ) in a predetermined crystal orientation. The piezoelectric member utilizes a transverse piezoelectric effect, and is preferably a (XYt) 45°-cut piece. The electrodes are preferably provided on surfaces that are parallel to the YZ plane.

First claim

What is claimed is:

1. A method for using a piezoelectric material, comprising:
using the piezoelectric material in an atmosphere of 400° C. or higher,
wherein the piezoelectric material comprises gehlenite represented by the compositional formula Ca 2 Al 2 SiO 7 .

2. The method according to claim 1 , wherein the piezoelectric material is included in a piezoelectric member.

3. The method according to claim 2 , wherein the piezoelectric member is included in a piezoelectric element and has a surface for receiving external stress and a side surface that is perpendicular to the surface for receiving external stress; and
the piezoelectric element comprises at least one pair of a first electrode and a second electrode that are placed on the side surface such that the first electrode is separated from the second electrode.

4. The method according to claim 3 , the electrodes are provided such that the electrodes cover substantially the whole of the side surface.

5. The method according to claim 3 , wherein the piezoelectric member is cut out from a crystal of the piezoelectric material along with an (XYt) 45° orientation.

6. The method according to claim 3 , wherein the electrodes are made of a material selected from the group consisting of Pt, Pd, and Ag—Pd alloy.

7. The method according to claim 3 , wherein the piezoelectric element is included in a pressure sensor comprising a diaphragm,
wherein the piezoelectric element is provided such that stress caused by external pressure on the diaphragm is transmitted to a stress-receiving surface of the piezoelectric member, and electric charges generated in the piezoelectric member by the thus-transmitted stress are detected via the electrodes.

8. The method according to claim 7 , comprising:
sensing an operation pressure with the pressure sensor,
wherein the pressure sensor is exposed to an environment of at least 400° C. during operation of an apparatus including the pressure sensor.

Assignees

• Energy Storage Mat Llc
• Sakai Chemical Industry Co

Inventors

• Tsurumi Takaaki

Classifications

• G01L23/10

  by pressure-sensitive members of the piezoelectric type · CPC title

• C30B29/34

  Silicates · CPC title

• G01L1/16 Primary

  using properties of piezoelectric devices · CPC title

• C30B15/00

  Single-crystal growth by pulling from a melt, e.g. Czochralski method (under a protective fluid C30B27/00) · CPC title

• C01B33/26 Primary

  Aluminium-containing silicates {, i.e. silico-aluminates} · CPC title