Many studies have been conducted on the action of corrosion inhibitors on corrosion product layers. There are varying opinions: the inhibitor may preferentially interact with the metallic surface or the existence of a corrosion scale enhances inhibitor adsorption. This paper will address the effect of the type of corrosion inhibitor active on the growth of iron carbonate. Our paper1 presented at NACExpo 2008 explored the synergistic interaction a quaternized amine compound has with iron carbonate. This work is a continuation and examines how imidazoline and phosphate ester compounds interact with iron carbonate. Tests were performed using the Rotating Cylinder Electrode (RCE) technique in conjunction with LPR (Linear Polarization Resistance), Tafel studies and EIS (Electrochemical Impedance Spectroscopy). Test samples composed of 1018 carbon steel were exposed to a pH 6.5 CO2-purged brine environment for the duration of the test. SEM/EDS (Scanning Electron Microscopy/Electron Dispersive Spectroscopy) were used in the analyses of the corrosion samples in order to observe the morphology, thickness and crystal structure of the iron scale layer. This work will provide insight on how various types of corrosion inhibitor actives affect the growth of iron carbonate.

Subject
Scanning electron microscopy, Corrosion rate, Iron carbonate, Scale inhibitors, Imidazolines, Phosphates, Chemical inhibition, Fluids, Iron carbonate scale, Corrosion inhibitors, Brines, Carbon steel, Linear polarization resistance
Keywords:
corrosion inhibition, iron carbonate, imidazoline, phosphate ester, linear polarization resistance, electrochemical impedance spectroscopy, potentiodynamic sweeps, scanning electron microscopy
© 2009 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).
2009
Association for Materials Protection and Performance (AMPP)
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