The current generation of stainless steels and superalloys have been designed to resist high temperature corrosion in atmospheres of high oxygen activity. These materials rely on the selective oxidation of chromium to form protective oxide scales on external surfaces at the gas/metal interface. The metallic components in coal gasification process equipment, on the other hand, will be exposed at high temperature to atmospheres of comparitively low oxygen activity. There is sufficient evidence from a range of laboratory test and pilot plant operating experience to indicate that under certain conditions of operation the majority of these materials are susceptible to severe and sometimes catastrophic attack by sulfidation and/or carburization. (Ref. 1, 2) Protective oxides are not formed at the gas/metal interface and unacceptable rates of corrosion result. Laboratory tests in simulated coal gasification environments have identified only two or three materials which promise extended service beyond a few thousand hours and even these can suffer severe attack under some conditions of operation. (Ref. 3)

Subject
Sulfur, Materials, Metal surfaces, Diffusion, Oxide formation, Gasification, Oxide scales, Oxide surfaces, Metals, Scale formation, Oxygen, Sulfides, Stainless steel
© 1977 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).
1977
Association for Materials Protection and Performance (AMPP)
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