Corrosion Behavior of Electropolished and Non-electropolished Ternary Nitinol Alloys

摘要

Electropolishing is a common technique for rendering a smooth mirror-like surface finish to implant materials. It is also known to improve a material's corrosion resistance. A current method to evaluate the corrosion resistance of biomedical implants is based on in-vitro corrosion tests (ASTM F2129-08). Cyclic polarization tests were conducted at 37 °C using phosphate buffer saline (PBS) as an electrolyte to evaluate the corrosion resistance of electropolished and non-electropolished Ni-Ti-Cu and Ni-Ti-Cr alloys. The effects of electropolishing on break down potential (E_b) and the difference between break down potential and rest potential (E_r), which is equivalent to the resistance to pitting corrosion were evaluated.