The Bureau of Mines has determined the corrosion rate of industrial electrogalvanized (EG) steel by dc and ac electrochemical techniques as compared to solution analysis by atomic absorption in deaerated molar ammonium sulfate. An evaluation of the zinc coatings obtained in an industrial-scale test has shown that coatings obtained from a waste-derived electrolyte out perform the normal industrial coating.

Impedance diagrams show that a slightly different frequency dispersion is obtained for the two different coatings studied. The time dependence of the zinc corrosion rate can be easily monitored by the use of impedance data over a frequency range of 0.1 to 11 Hz. Admittance plots provided the double-layer capacitance values, which indicate the presence or absence of surface corrosion products.

The results show that electro-chemical ac techniques can be applied to successfully determine the zinc corrosion rate of electrogalvanized steel in near-neutral media and that waste sources of zinc are viable for electrogalvanizing steel.

Subject
Coils, Zinc rich coatings, Corrosion rate, Impedance, Wiring, Inspection, Capacitance, Impedance measurements, Oxide surfaces, Steel, Zinc, Polarization resistance, Samples
© 1986 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).
1986
Association for Materials Protection and Performance (AMPP)
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