Corrosion occurs when AC is conducted to a metal through an electrolyte. Alternating current produces cyclic changes in the polarity of the electrode. Each half-cell reaction has different accumulative effects. For instance, the anodic half cycle can lead to corrosion or pitting whereas the cathodic half cycle can lead to hydrogen charging and possibly cracking.

AC produces a shift in the electrode potential, however the direction and magnitude of the shift depend on the intensity of the AC. Pitting is usually observed after sufficient time.

Studies have been conducted to explain the phenomena and identify the possible implications for the design of corrosion protection systems such as cathodic protection.

Electrochemical impedance spectroscopy (EIS), and cyclic polarization have been used to determine the effect of AC and induced magnetic fields. Characterization by scanning electron microscopy of the surface has also been performed.

Subject
Pits, Circuits, Electrochemical impedance spectroscopy, Cathodic protection, Corrosion rate, Metal surfaces, Density, Anodic reactions, Negative potentials, Current densities, Alternating current corrosion, Pitting, Electrode potential
Keywords:
AC corrosion, waveform, pitting, hydrogen charging, potential shift
© 2011 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).
2011
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.