Based on the mass transport in the stress corrosion crack, a mathematical expression of potential distribution along the stress corrosion crack is deduced. From this mathematical expression and the E-pH diagram for H2O, a new mechanism for hydrogen generation in the stress corrosion crack i.e. H+ partial potential drop mechanism, is proposed. Following this mechanism, the relationship between hydrogen generation and affecting factors, such as current density of anodic dissolution inside the crack, pH value, partial resistivity of H+ ion, dimension of the crack and potential of the metal, is discussed. The mechanism is verified by experimental measurement results of the H+ partial potential drop with microelectrodes placed in an artificial crack on AISI 410 stainless steel in 3%NaCl solution.

Subject
Bulk solution, Density, Solutions, Bubbling, Metals, Anodic current, Cations, Electrochemical potential, Cracks, Stress corrosion cracking, Electrolytes, Electrode potential, Hydrogen
Keywords:
Stress corrosion cracking, hydrogen generation, thermodynamics, hydrogen embrittlement microelectrode
© 1995 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).
1995
Association for Materials Protection and Performance (AMPP)
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