Effects of Shape and Surface Modification on the Corrosion of Nitinol Alloy Wires Exposed to Saline Solutions
The corrosion behaviour of Nitinol wire that was chemically etched and mechanically polished was studied in a corrosive 0.9 % saline solution. The electrochemical corrosion tests conducted on the as-received straight and curved wires of nitinol included open circuit potential (OCP) measurement, polarisation resistance and Tafel plots. The chemically etched looped wires exhibited the highest recorded corrosion potential, Ecorr and the lowest values of corrosion current, icorr. The results of the OCP measurements and polarisation resistance, combined with scanning electron microscopy (SEM) indicated the presence of a protective passive corrosion-resistant film on the chemically etched wires. The aim of the current investigation is to study the corrosion and pitting resistance behaviour of nitinol wire with different surface finishes.
KeywordsShape Modification Surface Corrosion Biomedical alloys Medical devices
We would like to acknowledge support for this investigation by Mr. Tim Ashton, Vice-president of R&D at Vascutek (Terumo), Scotland.
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