Implants

1. A method of producing a piezoelectric device, the method comprising the steps of

a. providing a material comprising a polycrystalline HA component,

b. texturing the material by uniaxially pressing the material to impart one of the limiting symmetries ∞ mm, ∞, or ∞2 to the HA component,

c. faceting the textured material at 0°, 45°, or 90° to a texturing direction depending on the limiting symmetry imparted by texturing, and

d. poling the textured and faceted material by applying an electric field between 0.1 kVcm −1 and 90 kVcm −1 , the direction of poling depending on the limiting symmetry imparted during texturing.

2. The method as claimed in claim 1 , wherein the uniaxial pressing comprises application of a uniaxial pressure between 30 MPa and 250 MPa, and preferably between 50 MPa and 150 MPa.

3. The method as claimed in claim 1 , wherein the uniaxially pressed material is fired between 800° C. and 1700° C., preferably between 1000° C. and 1300° C.

4. The method as claimed in claim 3 , wherein the uniaxially pressed material is fired in a steam environment.

5. A method as claimed in claim 3 , wherein an electric field is applied during firing.

6. The method as claimed in claim 3 , wherein an electric field is applied in an environment of ionised gas during firing.

7. The method as claimed in claim 6 , wherein the electric field is lower than the dielectric breakdown voltage of the material, between 0.1 kVcm −1 and 90 kVcm −1 .

8. The method as claimed in claim 1 , wherein the poling step comprises heating the material to a poling temperature, holding the material at the poling temperature for a poling period, and cooling the device back to a starting temperature.

9. The method as claimed in claim 1 , wherein the poling step comprises heating the material to a poling temperature, holding the material at the poling temperature for a poling period, and cooling the device back to a starting temperature; and wherein the poling temperature is between 40° C. and 650° C., and preferably between 150° C. and 450° C.

10. The method as claimed in claim 1 , wherein the poling step comprises heating the material to a poling temperature, holding the material at the poling temperature for a poling period, and cooling the device back to a starting temperature; and wherein the poling period is between 0.25hr and 6hr and preferably between 0.5hr and 2.0hr.

11. The method as claimed in claim 1 , wherein the HA component is anisotropic.

12. The method as claimed in claim 11 , wherein the anisotropy is over 5%.