Nitinol as a biomedical alloy has become an ideal material for use as self-expanding stents, grafts and other support systems due to its excellent superelasticity, biocompatibility and corrosion resistance. In terms of corrosion resistance, many studies have focused on the effects of surface treatments, oxide thickness, strain and presence of contaminants. However, in addition to these issues, a cardiovascular stent will also see the effect of pulsatile flow of blood through the artery. Thus, this work assessed the effects of fluid flow on the corrosion behavior of a super elastic Nitinol alloy. Electrochemical potentials were obtained on the Nitinol material while under flow conditions with a simulated body fluid. The electrochemical potential drifted positive after one week of continuous monitoring and ranged between --37 to 60 mV. Lower pH testing increased the overall corrosion potential. Post-test surface appearance was documented by Scanning Electron Microscopy (SEM). The flow conditions did not result in appreciable breakdown of the oxide layer.

Subject
Scanning electron microscopy, Test methods, Materials, Circuit potentials, Oxide layers, Wiring, Open circuits, Flow conditions, Fluids, Corrosion resistance, Corrosion potential, Potentiodynamic polarization, Electrode potential
Keywords:
Flow assisted corrosion, Nitinol, biomaterial
© 2012 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
2012
Association for Materials Protection and Performance (AMPP)
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