Piezoelectric composition and piezoelectric device

Patent metadata

Field	Value
Publication number	US-10811591-B2
Application number	US-201815914093-A
Country	US
Kind code	B2
Filing date	Mar 7, 2018
Priority date	Mar 9, 2017
Publication date	Oct 20, 2020
Grant date	Oct 20, 2020

Abstract

A piezoelectric composition comprises a plurality of crystal particles, wherein the piezoelectric composition includes bismuth, iron, barium, titanium, and oxygen; the crystal particles include a core and a shell covering the core; the average value of the contents of bismuth in the cores is expressed as C CORE % by mass, the average value of the contents of bismuth in the shells is expressed as C SHELL % by mass, and the C CORE is lower than the C SHELL ; and the number of all the particles comprised in the piezoelectric composition is expressed as N, the number of the crystal particles including the core and the shell is expressed as n, and n/N is 0.10 to 1.00.

First claim

What is claimed is:

1. A piezoelectric composition comprising a plurality of crystal particles, wherein
the piezoelectric composition includes bismuth, iron, barium, titanium, and oxygen;
the crystal particle includes a core and a shell covering the core;
an average value of contents of bismuth in the cores is expressed as C CORE % by mass,
an average value of contents of bismuth in the shells is expressed as C SHELL % by mass, and
the C CORE is lower than the C SHELL ; and
a number of all particles comprised in the piezoelectric composition is expressed as N,
a number of the crystal particles including the core and the shell is expressed as n, and
n/N is 0.10 to 1.00.

2. The piezoelectric composition according to claim 1 , wherein
the C CORE /C SHELL is 0.10 to 0.95.

3. The piezoelectric composition according to claim 1 , wherein
the piezoelectric composition is a sintered body.

4. A piezoelectric device comprising the piezoelectric composition according to claim 1 .

5. The piezoelectric device according to claim 4 , wherein
a piezoelectric constant d 33 of the piezoelectric composition to which an electric field of 0.1 to 2.0 kV/mm is applied is 200 pC/N or more.

Assignees

• Tdk Corp

Inventors

• Kitazaki Masashi
• Teranishi Keisuke
• Ishizaki Makoto

Classifications

• C04B35/26 Primary

  based on ferrites · CPC title

• C04B2235/75

  Products with a concentration gradient · CPC title

• C04B35/62897

  Coatings characterised by their thickness · CPC title

• C04B35/62886

  by wet chemical techniques · CPC title

• C04B2235/78

  Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures · CPC title