A Study on the Effect of Heat Treatment and Magneto-Electropolishing on in-Vitro Corrosion and Surface Properties of Ternary Nitinol

The development of new materials with tailored properties has found wide application in the medical, automobile and electronic industries. Ternary Nitinol alloys are a class of such emerging materials that require further research and development for application in such industries. Heat treatment is known to affect their transformation temperature, oxide layer composition, wettability and flexibility that directly impact their biocompatibility, performance and ease of installation. Magneto-electropolishing affords a thin and compact oxide layer that renders corrosion resistance, nano-textured morphology with reduced thrombogenicity. This investigation assessed the effect of heat treatment and magneto-electropolishing on the surface chemistry and corrosion resistance of NiTi10Ta. Martensitic phase transformation, a crucial parameter that determines the alloy’s application was determined using a differential scanning calorimeter (DSC).  Electrochemical impedance spectroscopy (EIS) and potentiodynamic tests were performed as per ASTM standards to assess corrosion resistance. Surface topography, morphology, surface chemistry and crystallinity were determined using atomic force microscopy (AFM), scanning electron microscopy (SEM)/ Energy-dispersive X-ray spectroscopy (EDS) and x-ray diffraction (XRD) respectively.