The performance of commercially available oilfield corrosion inhibitors has been evaluated by electrochemical impedance spectroscopy (EIS) in CO2 saturated 5 % sodium chloride solution. The results demonstrate that EIS is a feasible method for ranking oilfield corrosion inhibitor performance, and the inhibitors exhibit inhibition through different mechanisms. EIS can provide information on the inhibited film growth, and generate the parameters which are specific to a particular corrosion inhibition system. It is found that the high breakpoint frequency at 45° phase angle has excellent correlation with the corrosion rate in the inhibited system. The identification of this correlation is significant because there are advantages associated with measuring this parameter. A patent application has been filed for this discovery.

Subject
Circuits, Films, Electrochemical impedance spectroscopy, Water, Inhibitor performance, Corrosion rate, Inhibitor films, Solubility, Capacitance, Constants, Corrosion inhibitors, Immersion, Polarization resistance
Keywords:
EIS, CO2 corrosion, inhibitors, inhibition, frequency at 45° phase angle
© 1994 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).
1994
Association for Materials Protection and Performance (AMPP)
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