Dynamic Effect of Citrate on Electrolytic Deposition of Hydroxyaptite on Ti Surface

During electrolytic deposition process of hydroxyapatite(HA) on Ti surface, 2.4mmol/L citrate is added into the electrolyte containing 0.6mmol/L Ca2+ ion and 0.36mmol/L H2PO4- ion. The results show that the incubation period of the HA is prolonged significantly, and the HA crystals take the morphology of needlelike cone rather than the typical hexagonal prism. Through analyzing the deposition current, coating weight increment and crystal morphology changes, the whole deposition process is divided into 5 procedures: adsorption period, incubation period, eruptive growth period, extra-layer growth period and balanced growth period. Based on the further discussion of micro-mechanism of each period, the HA crystal growth model during electrolytic deposition process is proposed.