A study has been conducted to determine the feasibility of developing a single coating, a self-priming topcoat, for the protection of steel against corrosion. This concept has been demonstrated previously for aluminum substrates. Several corrosion inhibiting pigments were formulated into aliphatic polyurethane binders which are chemical and weather resistant. These coatings were applied to mild steel panels which had been zinc phosphate pretreated. The resulting coated specimens were evaluated for coating- substrate adhesion, flexibility, corrosion inhibition, and resistance to operational and environmental conditions (water, humidity, oil, fuel, etc.). All of the coatings exhibited adequate properties, including adhesion after a 7 day immersion in water at 65° C. Corrosion inhibition was evaluated by exposure in salt spray and SO2-salt spray, and by electrochemical impedance spectroscopy (EIS). All of the coatings exhibited good corrosion inhibiting properties. These results indicate that further development and optimization will likely result in a self-priming topcoat for a variety of steel applications.

Subject
Electrochemical impedance spectroscopy, Coating performance, Zinc rich coatings, Water, Coatings, Top coats, Substrates, Coating adhesion, Polyurethane coatings, Corrosion inhibitors, Steel, Barrier coatings, Corrosion inhibitive pigments
Keywords:
Corrosion, paints, coatings, self-priming topcoat, direct-to-metal, steel
© 1992 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).
1992
Association for Materials Protection and Performance (AMPP)
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