Electrochemical Stability of HAP-CNT/Ti6Al4V in Cell Culture Media

Ti6Al4V ELI alloys are widely used for orthopedic implants. These alloys have shown high corrosion resistance and biocompatibility. The limitation for their use are related to their poor bioactivity, hence the implants need a surface modification with materials that are able to promote bone tissue regeneration. With this objective, different surface modifications have been evaluated. Calcium phosphate coatings have shown high biocompatibility, bioactivity, and nontoxicity. The electrodeposition techniques show high efficiency, are easy to use, low cost and the coatings could be applied to irregular objects. In this work, we evaluated the electrochemical stability of Hydroxyapatite (HAP) with the incorporation of multiwall carbon nanotubes (MWCNT) on Ti6Al4V. We obtained HAP and HAP-MWCNT coatings on Ti6Al4V by pulsed electrodeposition. The obtained coatings were characterized by FTIR and XRD to evaluate the presence of MWCNT and calcium phosphates phases. The morphological and chemical composition evaluation was performed by SEM microscopy. The corrosion process was evaluated in cell culture media (RPMI-1640) by open circuit potential measurement, electrochemical spectroscopy impedance and linear sweep voltammetry to understand the kinetic of the dissolution. The results showed a relationship between the MWCNT incorporation, the resistivity of the coating and the stability of the passivation layer.