Latest understanding of protective rust layer on weathering steel and its application for structural steels is discussed. Phase transformation of the weathering steel rust layer during long-time exposure brings α -(Fe1-x, Crx)OOH, Cr-substituted goethite, as the final protective rust layer. It is said that the Cr content in the Cr-substituted goethite layer increases gradiently with reaching the rust/steel interface. This increase in the Cr content gives densely packed fine crystal structure and cation selective ability, which impedes the penetration of aggressive corrosives including anions such as Cl− and SO42−⁠. Quite recently, new surface-treatment technique employing Cr2(SO4)3 was proposed, which provides a possibility for obtaining the protective rust layer in a relatively short period even in the severe environment such as coastal region.

Subject
Steel structures, Protection practices, Materials, Corrosion rate, Sodium chloride solution, Penetration, Interfaces, Surface layers, Weathering, Steel, Rust, Corrosion protection, Cations
Keywords:
Cr-substituted goethite, protective rust, weathering steel, ion selectivity, surface treatment
© 1998 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).
1998
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.