Electrochemical impedance measurements and optical analysis have been made in artificial sea water on alkyd, epoxy-polyamide or ethyl-silicate zinc rich painted naval steel. Information concerning both the binder and the pigment volume concentration effects on the corrosion resistance of such systems was obtained from changes of the open circuit potential and impedance data at increasing exposure times as well as SEM observations.

Characteristic metal/coating system parameters were determined according to a transmission line model, which describes the painted metal/solution interface. These parameters correlate well with the gradual system deterioration as the galvanic effect and the barrier-like properties of the ZRP used as primers diminished progressively. Results can be interpreted in terms of corrosion processes going on extensively through pores and cracks of these coatings. The protective character of paints were ranked in agreement with their anticorrosive effectiveness in the highly aggressive medium employed.

Subject
Zinc rich coatings, Water, Pigments, Cathodic protection, Binders, Impedance, Epoxy coatings, Steel, Immersion, Corrosion protection, Zinc, Alkyds, Paints
Keywords:
zinc rich paints, zinc rich alkyd, zinc rich epoxy-polyamide, zinc rich ethyl-silicate, paints in sea water, electrochemical impedance spectroscopy, corrosion potential, standardized accelerated tests
© 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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