Electrophoretic coating of hydroxyapatite on pyrolytic carbon using glycol as dispersion medium

Hydroxyapatite (HA) coatings on pyrolytic carbon were produced via electrophoretic deposition (EPD) using glycol and ethanol as dispersion medium respectively. The effect of the solubility of HA in the dispersion medium on crack occurrence and adherence of the coating was investigated by means of scanning electronic microscope (SEM) and atomic absorption spectrometer (AAS). The results show that the solubility of HA in glycol is higher than that in ethanol. The usage of glycol as a dispersion medium can reduce the possibility of crack formation and enhance the adhesive strength between the coating and the carbon substrate. The green coatings can be sintered under vacuum at 1 000 degrees C whether the coatings are obtained using ethanol or glycol as dispersion medium. No HA decomposition was observed up to 1 000 degrees C by vacuum sintering by X-ray diffraction (XRD) analysis.