Flexible piezoelectric material, production and use thereof

• US 10,079,336 B2
• Filed: 01/13/2014
• Issued: 09/18/2018
• Est. Priority Date: 01/13/2014
• Status: Active Grant

• Current Assignee: Meggitt A/S (Meggitt PLC)
• Original Assignee: Meggitt A/S (Meggitt PLC)
• Inventors: Zawada, Tomasz, Hansen, Karsten, Astafiev, Konstantin, Ringgaard, Erling
• Primary Examiner(s): Hoban, Matthew E.
• Assistant Examiner(s): Edmondson, Lynne
• Application Number:
  US14/153,556
• Publication Number:
  US 20150200351A1
• Time in Patent Office: 1,709 Days
• Field of Search: 252 629 PZ, 252 629 R, 310358, 427100
• CPC Class Codes: H10N 30/074 by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
• CPC Class Codes: H10N 30/092 Forming composite materials
• CPC Class Codes: H10N 30/852 Composite materials, e.g. having 1-3 or 2-2 type connectivity

Abstract

A composite piezoelectric material, manufacturing of the composite material and use of this composite material in piezoelectric components are disclosed. More particularly, a piezoelectric thick film materials or piezoelectric paint being a composite piezoelectric material including piezoelectric particles randomly dispersed within a polymer matrix are disclosed. A paste of composite piezoelectric material including a matrix of polymer having a relative permittivity ≥3, normally ≥6, sintered piezoelectric particles having a relative permittivity in the range of 100-5000, normally in the range of 400-1000 and an average particle size between 1 and 50 μm, although the particles should be smaller than 1/10 of the final thickness of the final layer of piezoelectric material, and additives such as dispersing agents or thinner are disclosed where the final paste has a 0-3 connectivity pattern, a content of sintered piezoelectric particles between 15 and 75 vol %, normally between 40 and 60 vol %.

Claims

1. A method of manufacturing a piezoelectric paste and curing the paste into a piezoelectric element comprising:

pressing a ceramic piezoelectric active powder with a relative permittivity of about 400 into a solid unit;

sintering the solid unit;

crushing and milling the solid unit into piezoelectric particles;

mixing the piezoelectric particles with a binding matrix that has a permittivity of about 8 to form the piezoelectric paste, wherein the piezoelectric powder comprises between 40% and 50% by volume of the piezoelectric paste;

mixing the piezoelectric particles and binding matrix with a thinner until the viscosity of the piezoelectric paste is between 2 and 15 PaS;

applying a layer of the piezoelectric paste with a thickness between 10 and 300 micrometers to a substrate;

curing the layer of piezoelectric paste wherein a median diameter of the piezoelectric particles in the layer of piezoelectric paste is 1/10 or less a cured thickness of the layer of piezoelectric paste; and

poling the cured piezoelectric paste at an elevated temperature of 90°

Celsius for 10 minutes.

2. The method of claim 1, wherein the minimum thickness of the layer is comprised of a plurality of separately deposited thinner layers.

3. The method of claim 1, wherein the piezoelectric particles comprise 50% of the volume of the piezoelectric paste.

4. The method of claim 1, wherein the binding matrix is a polymer material.

5. The method of claim 1, wherein the binding matrix is a fluoride based polymer.

6. The method of claim 1, wherein the binding matrix is Polyvinylidene fluoride.

7. The method of claim 1, wherein the applying step is performed using screen-printing or pad-printing.

8. The method of claim 1, wherein the binding matrix is 8155 made by DuPont.

9. The method of claim 1, wherein the thinner is 8210 made by DuPont.

12. The method of claim 1, wherein the viscosity of the piezoelectric paste is measured at a shear rate equal to 33.3 (1/sec).

10. A method of manufacturing a piezoelectric paste and curing the paste into a piezoelectric element comprising:

pressing a ceramic piezoelectric active powder with a permittivity between 400 and 1000 into a solid unit;

sintering the solid unit;

crushing and milling the solid unit into piezoelectric particles;

mixing the piezoelectric particles with a binding matrix with a permittivity greater than or equal to 6 to form the piezoelectric paste, wherein the piezoelectric particles comprise between 40% and 60% by volume of the piezoelectric paste;

mixing the piezoelectric particles and binding matrix with a thinner until the viscosity of the piezoelectric paste is between 2 and 15 PaS;

applying a layer of the piezoelectric paste with thickness between 10 and 300 micrometers to a substrate;

curing the layer of piezoelectric paste wherein a median diameter of the piezoelectric particles is 1/10 or less a cured thickness of the layer of piezoelectric paste; and

poling the cured piezoelectric paste at an elevated temperature of 90°

Celsius for 10 minutes.

11. The method of claim 10, wherein the piezoelectric particles comprise about 50% by volume of the piezoelectric paste.

13. The method of claim 10, wherein the viscosity of the piezoelectric paste is measured at a shear rate equal to 33.3 (1/sec).

14. The method of claim 10, wherein the binding matrix is a polymer material.

15. The method of claim 10, wherein the binding matrix is a fluoride based polymer.

16. The method of claim 10, wherein the binding matrix is Polyvinylidene fluoride.

17. The method of claim 10, wherein the applying step is performed using screen-printing or pad-printing.

18. The method of claim 10, wherein the ceramic piezoelectric active powder is Lead-Free.