This paper covers one of the building blocks required to complete a mechanistic CO2 / H2S corrosion model: electrochemistry of carbon steel CO2 corrosion in the presence of traces of H2S (3-250 ppm in the gas phase). Electrochemical impedance spectroscopy and linear polarisation resistance were used to investigate the mechanism of CO2/H2S corrosion in a glass cell at room temperature, at atmospheric pressure, pH5, using a rotating cylinder electrode at 1000 rpm.

Very thin sulphide film was formed on the steel electrode in all experiments with H2S. At low concentrations (<15 ppm) the sulphide films reduced the corrosion rate while at higher concentrations of H2S (up to 250 ppm) the trend was reversed and a mild increase of the corrosion rate was seen.

Subject
Electrochemical impedance spectroscopy, Water, Hydrogen concentration, Corrosion rate, Sulfide films, Sodium chloride, Impedance, Sodium chloride solution, Film formation, Carbon steel, Immersion, Linear polarization resistance, Corrosion potential
Keywords:
CO2 corrosion, H2S, electrochemical impedance spectroscopy, linear polarisation resistance
© 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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