According to published data, molybdates are very efficient corrosion inhibitors for iron in distilled water.1,2  Molybdates have been shown to be corrosion inhibitors also in a more realistic environment such as neutral or basic solutions containing chlorides, sulfates and some other ions or solutions which would approximate cooling tower water.3,4  Unfortunately, published data indicate that large amounts of molybdenum are needed to inhibit corrosion of iron in the presence of chloride and other ions. Zinc and chromate systems, because of their great effectiveness, are used as corrosion inhibitors in cooling tower environment; however, because of the toxicity of chromates and toxicity of zinc to aquatic life the future use of these inhibitors probably will be greatly curtailed. Molybdates, on the other hand, are of very low toxicity, and, because of this low toxicity, it has been suggested that molybdates could be used to replace zinc and chromate as inhibitors in aqueous systems. This work has been undertaken to clarify the role of molybdate ions as an inhibitor in aqueous solutions containing chlorides and other ions, and thereby provide some guidance for the development of molybdate inhibitor systems.

Subject
Ions, Corrosion rate, Iron, Chloride solutions, Corrosion inhibitors, Steel, Oxygen, Polarization, Chlorides, Electrodes, Corrosion potential, Potentiodynamic polarization, Electrode potential
© 1975 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).
1975
Association for Materials Protection and Performance (AMPP)
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