This research evaluates the galvanic corrosion resistance of three High-velocity-oxy-fuel and one plasma sprayed coatings on steel substrates coupled to graphite. Galvanic corrosion resistance was measured by coupling the coated steel to graphite through a zero-resistance-ammeter and recording the current flowing between the coated steel and the graphite with time. In addition, superimposition of anodic polarization data for the coated steel panels on top of the cathodic polarization curve for graphite was used to evaluate the protective nature of each of the coatings. In order to understand how coating microstructure influenced performance, a metallographic investigation of the coatings was also conducted. Of the coatings evaluated, the sealed, plasma sprayed zirconia-based coating exhibited the best galvanic compatibility with graphite. The excellent performance of this coating was attributed to the ability of the sealer to infiltrate the network of pores and oxide layers in the coating, blocking the permeation of the seawater.

Subject
Nickel coatings, Coated steel, Coating performance, Coatings, Spray coating, Artificial seawater, High velocity oxy fuel spraying, Plasma, Graphite, Rust, Sealers, Galvanic current, Thermal spray coatings
© 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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