Characterization of Electrodeposited Hydroxyapatite Coating onNanoporous Anodized Titanium

摘要

The surface of pure titanium was treated by electrochemical anodization in 0.50rnM H3PO4 + 0.14 M NH4F solution. This treatment has generated titania nanotubes.rnHydroxy apatite (HAP) was implanted into the nanotubes using electrochemicalrndeposition. Adsorbed phosphate ions, after the anodization, facilitated the nucleation ofrncalcium phosphate material inside the nanotubes that resulted in vertical growth ofrnapatite crystals. This process was followed by post treatment in 1.0 M NaOH at 100℃rnfor 1 hr. Bond strength of the coating was found to be good, and cohesive mode ofrnfailure of the coating was observed after tensile testing. The electrochemical studies inrnRinger's solution revealed that the coated samples exhibit higher corrosion resistancernthan the bare metal. The coated samples have nobler open circuit potential (OCP)rnvalues and higher breakdown and protection potentials. The smaller size of the loopsrnobtained indicates the stability of HAP/Ti interface against corrosion attack and thernfaster repassivation tendency of the HAP coatings.