Effects of applied voltages on hydroxyapatite coating of titanium by electrophoretic deposition.

Hydroxyapatite (HA) coatings were deposited on titanium substrates by electrophoretic deposition (EPD) at constant voltage and dynamic voltage, respectively. Various surface morphologies were observed under different type of voltages. Under a constant voltage of 20 V, a dense HA coating could be prepared. Under a constant voltage of 200 V, big HA particles were deposited and the coating was porous. Under a dynamic voltage, a continuous gradient HA coating could be obtained. HA coatings were characterized with a field emission-scanning electron microscopy (FE-SEM) and an X-ray diffraction (XRD). XRD indicated no significant HA decomposition when the coatings were sintered for 2 h at 800 degrees C.