This paper presents the first step of a mathematical model of the propagation period of crevice corrosion using a commercial finite element program. Potential and concentration profiles inside the crevice are in good agreement with previous studies. A detailed inspection of the crevice mouth indicates that accounting for the equilibrium conditions by using very high rate constants leads to the appearance of a sharp domain where the equilibria are not fulfilled. This discrepancy can be only partially suppressed, since increasing a rate constant for a reaction may destabilize the equilibrium of another reaction. This model permits the prediction of the occurrence of gaseous hydrogen formation. It is shown that gas bubbles appear under anodic potential, even with low ohmic drops, since the proton reduction rate is supposed to be pH dependent and the pH inside the crevice is mainly controlled by the hydrolysis reaction.

Subject
Modeling, Hydrogen concentration, Diffusion, Reaction kinetics, Bulk solution, Lead, Constants, Crevices, Anodic reactions, Crevice corrosion, Electric potential, Chemical reactions, Hydrogen
Keywords:
crevice corrosion model simulation
© 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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