To monitor the corrosion rate of materials of boiler tubes in simulated waste incineration environment, A.C. impedance measurements were carried out for Alloy625, SUS347H and STBA24 embedded in NaCl- KCl- Na2SO4- K2SO4 -Al2O3 mixed synthetic ash deposit at 600°C. Though the ash includes some non-melting component, A.C. impedance measurements can be applied to evaluate corrosion rates in the same manner the corrosion of materials immersed in molten salts. Supposing the difference of impedance between the low frequency and high frequency (ΔR) as polarization resistance, a linear relation was obtained between 1/ΔR and corrosion losses in air, air-0.1vol. %HCl and air-10vol. %H2O atmospheres. The HCl addition in accelerated the corrosion of all specimens by reducing basicity of the molten salt. On the other hand, the H2O addition reduced the corrosion of Alloy625, but it accelerated the corrosion of SUS347H and STBA24.

Subject
Materials, Salts, Corrosion rate, Tubes, Atmosphere, Impedance, Impedance measurements, Corrosion losses, Weight loss, Ash, Boilers, Deposit corrosion, Electrodes
Keywords:
waste incineration, high temperature corrosion, hot corrosion, chloride, sulfate, A.C.impedance measurement, corrosion monitoring
© 1997 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).
1997
Association for Materials Protection and Performance (AMPP)
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