Corrosion behavior of spark-plasma-sintered reduced graphene oxide reinforcedTi6Al4V composite in simulated body fluid

Corrosion behavior of Ti6Al4V and rGO/Ti6Al4V composites fabricated by spark plasma sintering (SPS) was systematically investigated in stimulated body fluid (SBF) using electrochemical measurements including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Results showed that the rGO/Ti6Al4V composites exhibit enhanced corrosion resistance, especially corrosion rate of the 0.54rGO/Ti6Al4V composite (∼7.10 × 10⁻⁴ g·m⁻²·h⁻¹) is only about one-seventh of that of monolithic Ti6Al4V (∼48.3 × 10⁻⁴ g·m⁻²·h⁻¹). As compared with Ti6Al4V sample, preferential dissolution of the rGO/Ti6Al4V composites are liable to occur in the early SBF immersion stage, and rGO is believed to do credit to rapid passivation on the composite surface in virtue of the added rGO with excellent electric conductivity acting as the micro-cathode and fine basket-weave microstructure induced by these rGO. Meanwhile, the inherent inert and hydrophobic nature of rGO within the passivation film would act as a barrier to resist infiltration of halide ion, and therefore the addition of rGO into Ti6Al4V matrix is capable of inhibiting localized breakdown of passive film. Above results strongly suggest that rGO/Ti6Al4V composite could be a promising candidate for biomedical applications.