Piezoelectricity in unpoled hydroxyapatite ceramics

Piezoelectric Sensors have gained significant importance in recent years due to conversion of mechanical stress into electrical current. Hydroxyapatite is excellent biocompatible, non-toxic and piezoelectric material for biomedical applications. In this paper, pellets of hydroxyapatite are prepared by Spark Plasma Sintering (SPS) by two different powders. The samples were characterized by the X-Ray diffractometer (XRD), Atomic Force Microscope (AFM), Piezometer and Piezo-response Microscope. Macroscopically these ceramics show weak longitudinal piezoelectricity. Local piezoelectric coefficients showed both in plane and out of plane piezoelectricity with magnitude as high as 4-5pC/N. Further improvements and tuning of piezoelectric properties are possible through thermoelectric poling and creating proper resonator structure for use as sensors and actuators.