Several parameters influencing the life cycle of Fe-20Cr-Al were investigated. For industrially used chemical compositions, the foil thickness of 50 microns is critical for applications in catalytic converters, since exponential scale growth due to surface aluminium depletion has to be considered. Oxidation resistance can also be increased by alloying with yttrium and hafnium as reactive elements. These are superior to those of cerium mischmetal or yttrium by alone. Overdoping can cause very high oxidation rates and severe internal oxidation and has to be avoided. Furthermore increasing the aluminium content is helpfid as well. Since this may lead to embrittlement of conventionally produced materials, a new production technique was developed, which is based on aluminising of Fe-Cr at lower thickness. This techniques results in higher aluminium contents in near surface regions which are quite sufficient for increasing oxidation resistance.

Subject
Scanning electron microscopy, Foil, Materials, Iron oxide, Metal surfaces, Diffusion, Oxide formation, Aluminum, Constants, Oxide scales, Elements, Aluminum alloys, Oxidation
Keywords:
Fe-Cr-Al, oxidation resistance, aluminium, reactive elements, production technique
© 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)
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