Lead-free piezoelectric material

Patent metadata

Field	Value
Publication number	US-9780295-B2
Application number	US-201314759569-A
Country	US
Kind code	B2
Filing date	Jan 28, 2013
Priority date	Jan 28, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A lead-free piezoelectric ceramic material has the general chemical formula xBiCoO3-y(Bi0.5Na0.5)TiO3-z(Bi0.5K0.5)TiO3, xBiCoO3-y(Bi0.5Na0.5)TiO3-zNaN-bO3, xBiCoO3-y(Bi0.5Na0.5)TiO3-zKNbO3, xBiCoO3-yBi(Mg0.5Ti0.5)O3-z(Bi0.5Na0.5)TiO3, xBiCoO3-yBa-TiO3-z(Bi0.5Na0.5)TiO3, or xBiCoO3-yNaNbO3-zKNbO3; wherein x+y+z=1, and x, y, z≠0.

First claim

What is claimed is:

1. A lead-free piezoelectric ceramic material having the general chemical formula:
xBiCoO 3 -y(Bi 0.5 Na 0.5 )TiO 3 -zNaNbO 3 ;
xBiCoO 3 -y(Bi 0.5 Na 0.5 )TiO 3 -zKNbO 3 ;
xBiCoO 3 -yBi(Mg 0.5 Ti 0.5 )O 3 -z(Bi 0.5 Na 0.5 )TiO 3 ; or
xBiCoO 3 -yBaTiO 3 -z(Bi 0.5 Na 0.5 )TiO 3 ;

wherein x+y+z=1, and x, y, z≠0.

2. The lead-free piezoelectric ceramic material of claim 1 , wherein 0.01≦x≦0.2.

3. The lead-free piezoelectric ceramic material of claim 1 , wherein x≦0.2.

4. The lead-free piezoelectric ceramic material of claim 1 , wherein the ceramic material has an effective piezoelectric strain coefficient d 33 * of about 150-500 pm/V.

5. The lead-free piezoelectric ceramic material of claim 1 , wherein the ceramic material has a maximum electromechanical strain value of about 0.1% to 0.3%.

6. The lead-free piezoelectric ceramic material of claim 1 , wherein the ceramic material has a remanent polarization of about 25-40 μC/cm 2 .

7. The lead-free piezoelectric ceramic material of claim 1 , wherein the ceramic material has a remanent polarization equal to or exceeding that of a lead-based piezoelectric material.

8. The lead-free piezoelectric ceramic material of claim 1 , wherein the ceramic material is a piezoelectric layer of a thin film stack, and wherein the piezoelectric layer is situated between first and second metal layers of the thin film stack.

9. The lead-free piezoelectric ceramic material of claim 8 , wherein the thin film stack is an actuator for a fluid ejection device.

10. A lead-free piezoelectric ceramic material having the general chemical formula:
xBiCoO 3 -y(Bi 0.5 Na 0.5 )TiO 3 -z(Bi 0.5 K 0.5 )TiO 3 ;
xBiCoO 3 -y(Bi 0.5 Na 0.5 )TiO 3 -zNaNbO 3 ;
xBiCoO 3 -y(Bi 0.5 Na 0.5 )TiO 3 -zKNbO 3 ;
xBiCoO 3 -yBi(Mg 0.5 Ti 0.5 )O 3 -z(Bi 0.5 Na 0.5 )TiO 3 ;
xBiCoO 3 -yBaTiO 3 -z(Bi 0.5 Na 0.5 )TiO 3 ; or
xBiCoO 3 -yNaNbO 3 -zKNbO 3 ;

wherein x+y+z=1, and x, y, z≠0; and
wherein the ceramic material has an effective piezoelectric strain coefficient d 33 * of 180-500 pm/V.

11. The lead-free piezoelectric ceramic material of claim 10 , wherein x≦0.2.

12. The lead-free piezoelectric ceramic material of claim 10 , wherein the ceramic material has a maximum electromechanical strain value of 0.15% to 0.3%.

13. The lead-free piezoelectric ceramic material of claim 10 , wherein the ceramic material is a piezoelectric layer of a thin film stack, and wherein the piezoelectric layer is situated between first and second metal layers of the thin film stack.

14. The lead-free piezoelectric ceramic material of claim 13 , wherein the thin film stack is an actuator for a fluid ejection device.

Assignees

• Hewlett Packard Development Co Lp
• Oregon State Univ Office Of Tech Transfer

Inventors

• Patterson Eric Andrew
• Cann David
• Mardilovich Peter

Classifications

• B41J2202/03

  Specific materials used · CPC title

• C04B2235/3251

  Niobium oxides, niobates, tantalum oxides, tantalates, or oxide-forming salts thereof · CPC title

• C04B2235/3201

  Alkali metal oxides or oxide-forming salts thereof · CPC title

• B41J2/14233

  of film type, deformed by bending and disposed on a diaphragm · CPC title

• C04B2235/3275

  Cobalt oxides, cobaltates or cobaltites or oxide forming salts thereof, e.g. bismuth cobaltate, zinc cobaltite · CPC title