Surface Activation of Ni-Ti Alloy Using Electrochemical Process for Biomimetic Deposition of Hydroxyapatite Coating

Electrochemical depositions of calcium phosphide layer on ni-ti alloy in concentrated simulated bodyflood (sbf×5) were carried out by cathodic electrodeposition. this layer was deposited on ni-ti alloysubstrate under 10ma/cm2 current density for 2 hours at room temperature. then, in order toinvestigate the bioactivity of the pre-calcified samples, they were put in sbf for 1 and 3 days at roomtemperature. the microstructure, chemical composition, and bioactivity of the coatings were evaluated using scanning electron microscopy(sem), energy dispersive spectroscopy(eds), x-raydiffraction(xrd) and fourier transform infrared spectroscopy(ftir) techniques. results showed thatthe activation of the surface of the ni-ti alloy by electrochemical process can significantly enhance the biomimetic deposition during time. on the other hand, by increasing immersion time of pre-calcified samples in sbf from 1 to 3 days, the biomimetic coating uniformly covered the surface of the sample. the ratio of the ca/p for the pre-calcified sample after immersion in sbf for 3 days was about 1.5 which is very close to the ca/p ratio of stoichiometric hydroxyapatite.