Synergistic effects of environment friendly compounds of sodium silicate and 1-hydroxyethylidene 1,1 diphosphonic acid (HEDP) on mild steel corrosion control in neutral and aerated soft water solutions have been investigated using electrochemical impedance spectroscopy and Tafel polarization techniques. The impedance and polarization results revealed that inhibitors mixtures have shown synergistic effects at lower value of HEDP. At 15ppm silicate and 10ppm HEDP showed optimum enhanced inhibition compared to their individual effects. The co-addition of 15ppm HEDP and 15ppm silicate have shown antagonistic behaviour. These observations have been supported by scanning electron microscopy (SEM) images, illustrating that the surface homogeneity increases in case of inhibitors mixture application and this provides good protection to mild steel against corrosion in soft water solution.

Subject
Scanning electron microscopy, Steel surfaces, Water, Silicates, Mixtures, Corrosion products, Solutions, Sodium, Film formation, Corrosion inhibitors, Surface layers, Steel, Polarization
Keywords:
silicate, HEDP, corrosion inhibitors, soft water
© 2007 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).
2007
Association for Materials Protection and Performance (AMPP)
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