Surface Roughening of Platinum Wire: An Electrochemical and Mechanical Approach

Abstract

In order to make implanted electrodes MRI safe several methods have been explored. One of those methods involves increasing AC resistance by roughening the surface of the implanted platinum wires. This thesis explores an electrochemical and a mechanical approach to reliably induce 15 micro meter deep surface defects. The electrochemical approach dissolves the outermost layer of the wire and redeposits a porous layer on the surface that does not grow more than 2 micro meters thick. It is predicted that this layer may be grown to desired thickness if the source of platinum comes from within the solution treatment takes place in rather than the treated wire itself. The mechanical approach induces fatigue cracks that grow predictably and can be controlled to desired size. The limitations are the small amount of wire that may be treated at a time through rotational fatiguing, and the initial quality of the treated wire. High quality wire and an ultrasonic fatigue setup may remedy these limitations.