The magnitude of electrochemical potential noise of aluminum alloys 1100, 2024 and 5052 in naturally aerated chloride solutions decreased approximately with increasing square root of specimen surface area in contact with the electrolyte. The experimental behavior was consistent with the predictions of a simplified model that assumed random generation of similar independent anodic events at a rate proportional only to the specimen area. The potential fluctuation from each individual event decreased with increasing specimen area due to the corresponding increase in interfacial admittance. This factor, coupled with statistical addition of the contribution of individual events, resulted in a model output reproducing the observed inverse square root dependence on area. The model applicability was demonstrated by nearly replicating experimental behavior when using as input interfacial polarization parameters that were obtained from independent electrochemical impedance and potentiodynamic tests.

Subject
Electrochemical impedance spectroscopy, Water, Trends, Metal surfaces, Electrochemical noise, Slopes, Capacitance, Anodic reactions, Immersion, Aluminum alloys, Alloys, Electrochemical potential, Step potential
Keywords:
Electrochemical Noise, Surface Area Dependence, Aluminum, Chloride, Modeling, Impedance, Capacitance
© 2004 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).
2004
Association for Materials Protection and Performance (AMPP)
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