Purified silica sand was modified by the addition of various amounts of chloride or sulfate ion to increase the concentration in milli-equivalents per 100 grams of dry sand. Corrosion rates were determined by using the Stern-Geary polarization resistance method at various concentrations of each ion and with mixtures of the ions. The corrosion rates were determined in the absence of AC and with a current density of 4.0 mA/cm impressed on the wires while the polarization resistance measurements were being made. It was found that the maximum rate of corrosion in the absence of AC was about 4.1 mpy for chloride at 30 meq per 100 grms. of dry sand and 0.1 mpy at 20 meq. for sulfate. Impressing AC decreased the maximum for chloride to 2.7 mpy at 30 to 40 meq. but increased the maximum for sulfate to about 0.4 mpy for concentrations below 20 meq. The negative shifts in the corrosion potentials of copper in several concentrations of the ions with AC current density were observed and that in sulfate was found to be at least 10 times that in chloride except on low concentrations of the anions.

Subject
Anions, Cathodes, Sand, Corrosion rate, Sulfates, Cathodic current, Wiring, Anodic current, Copper, Chlorides, Soil, Corrosion potential, Anodes
© 1984 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).
1984
Association for Materials Protection and Performance (AMPP)
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