The importance of calcareous deposits to the effectiveness and efficiency of cathodic protection in submerged ocean situations is generally recognized. Such deposits are a consequence of a pH increase of the electrolyte adjacent to the metal surface, due to the cathodic current, and the fact that the solubility limit of most inorganic compounds, noteably CaCO3, MgCO3 and Mg(OH)2, decreases with increasing pH. Regarding the significance of these films to marine cathodic protection there either is evidence that or it has been suggested that calcareous deposits 1) reduce the flux of dissolved oxygen from bulk solution to the metal, 2) reduce the current density necessary to affect a given cathodic potential, 3) inhance the "throwing power" of the cathodic protection and 4) reduce the overall magnitude of local action cells (uniform corrosion) if cathodic protection is removed.1-5 

Subject
Films, Steel surfaces, Water, Cathodic protection, Cathodic potential, Metal surfaces, Current densities, Film thickness, Cathodic current density, Scale formation, Deposit corrosion, Electrolytes, Calcareous deposits
© 1980 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).
1980
Association for Materials Protection and Performance (AMPP)
You do not currently have access to this content.