Hydroxyapatite coating by electrophoretic deposition at dynamic voltage.

The aim of this study was to evaluate hydroxyapatite (HA) coatings produced by dynamic voltage during electrophoretic deposition (EPD). Dynamic voltages from 0 to 200 V were incrementally applied in three interims. The as-deposited coating was sintered at 800 degrees C and its properties evaluated. Structure and phase analyses of both as-deposited and sintered coatings were evaluated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The HA coatings obtained by dynamic voltage consisted of two layers. While the inner layer was dense and firmly attached to the substrate and contained fine HA particles, the outer layer was porous and contained bigger particles. Repeated deposition was applied to increase the thickness of the coatings. SEM analysis showed that these coatings were free of cracks. In addition, decomposition of HA coatings was not observed until 800 degrees C.