Many semiconducting minerals have sufficient conductivity to permit electrochemical reactions on their surfaces. Consequently, galvanic interactions will occur when such minerals are coupled to metals or other conducting minerals. Accelerated galvanic corrosion of metals coupled to noble minerals is quite likely, because most minerals exhibit potentials in solution which are noble to the corrosion potentials of metal alloys. Anodic and cathodic polarization diagrams can be used to predict the galvanic corrosion rates to be expected from any given galvanic couple in a particular corrosive electrolyte. Polarization diagrams in sulfuric acid for numerous minerals and alloys are presented, and some examples are extracted from the diagrams to demonstrate how the curves can be utilized to estimate the likelihood of galvanic corrosion and the reaction rates to be expected in metal-metal, metal-mineral, and mineral-mineral couples. Effects of relative surface area, application to initiation of pitting corrosion, and limitations of the method are also discussed.

Subject
Corrosion rate, Predicted corrosion rate, Metal surfaces, Sulfuric acid, Minerals, Polarization curves, Metals, Steel, Sulfides, Polarization, Galvanic current, Alloys, Corrosion potential
© 1988 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).
1988
Association for Materials Protection and Performance (AMPP)
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