Quantitative Analyses of crystalline compositions have been performed on the rusts which formed on the outer panel surface and in the crevice of the lapped portion on vehicles used in North America. X-ray diffraction using the internal standard technique was employed to quantitatively analyze the rust composition. Characteristic regions of the rust compositions were found in the α-FeOOH / (γ-FeOOH + Fe3O4) / (β-FeOOH + amorphous) ternary diagram. The rust from the crevice in the lapped portion contained more (γ-FeOOH + Fe3O4) than the rust from the outer steel panels. The amount of β- FeOOH was large on galvanized parts, reaching a maximum of 13 percents. The compositions which were formed in salt spray test differed from those found on actual vehicles. A ternary diagram devised in the present study is useful in correlating the results obtained in accelerated corrosion tests with those found on automobiles which have corroded under service conditions.

Subject
Accelerated corrosion tests, Steel panels, Coated steel, Materials, Composition, Corrosion products, Crevices, Corrosion modeling, Salt spray corrosion testing, Steel, Rust, Automotive, Coating vehicles
Keywords:
rust, vehicle, X-ray, α-FeOOH, β-FeOOH, γ-FeOOH, Fe3O4, wet and dry, accelerated corrosion test
© 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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