Lead-free piezoelectric material

Patent metadata

Field	Value
Publication number	US-2015372221-A1
Application number	US-201314759569-A
Country	US
Kind code	A1
Filing date	Jan 28, 2013
Priority date	Jan 28, 2013
Publication date	Dec 24, 2015
Grant date	—

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 -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.

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.

Assignees

• Hewlett Packard Development Co

Inventors

• Patterson Eric Andrew
• Cann David
• Mardilovich Peter

Classifications

• C04B2235/3298

  Bismuth oxides, bismuthates or oxide forming salts thereof, e.g. zinc bismuthate · CPC title

• C04B2235/3275

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

• C04B35/465

  based on alkaline earth metal titanates · CPC title

• C04B35/4682

  based on BaTiO3 perovskite phase · CPC title

• C04B2235/3251

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