EFFECT OF ANODIC OXIDATION ON THE CORROSION BEHAVIOR OF NICKEL-TITANIUM SHAPE MEMORY ALLOYS IN SIMULATED BODY FLUIDS (SBF)

The effect of anodic oxidation of a NiTi shape memory alloy in sulfuric acid electrolyte on its surface characteristics was studied. Surface roughness was measured by roughness tester. Surface morphology was studied using optical microscopy (OM) and scanning electron microscopy (SEM). Corrosion behavior was specified by recording Potentiodynamic polarization curves and measuring the content of Ni ions, released into a SBF solution using atomic absorption spectroscopy (AAS). Fourier transformation infrared radiation (FT-IR) and energy dispersive spectroscopy were employed to verify the biocompatibility of the anodized and bare alloys after submersion in SBF. It was shown that anodic oxidation in sulfuric acid significantly increases corrosion resistance and biocompatibility. This layer improves corrosion resistance and Ni ion-release resistance by impeding the direct contact of the alloy with the corrosion mediums i.e. Ringer and SBF solutions. The TiO2 oxide layer also decreases the releasing of Ni ions in to SBF solution.