Cathodic protection, normally used in conjunction with a coating, ensures protection at areas where the coating is damaged or displaced. However, it can cause disbondment of the coating around such areas and encourage ingress of electrolyte. Tests carried out at a range of temperatures show that some coatings having good results at room temperature give very poor results at elevated temperatures whereas others give significantly better results.

This appears to depend on the precise construction of the coating.

It follows that raising the temperature to accelerate testing can give misleading results.

It can also be shown that adhesion strength of a coating is no indication of the coating's resistance to cathodic disbonding.

Limiting the damage caused by impact and indentation would reduce sites for disbondment but tests suggest that even severe indentation does not necessarily provide a site for cathodic disbondment.

Subject
Holidays, Coatings, Piping, Adhesives, Indentation, Cathodic protection, Tape, Fusion bonded epoxy coating, Coating damage, Cathodic disbondment, Coating adhesion, Coal, Electrolytes
© 1988 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).
1988
Association for Materials Protection and Performance (AMPP)
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