Ac impedance and dc polarization tests of 304 stainless steels coated by cathodic arc plasma deposition (CAPD) titanium nitride and zirconium nitride were conducted in aqueous chloride solution. Cyclic polarization data suggested passive films were formed over the nitride coatings which are most likely hydrated titanium oxide and zirconium oxides. ESCA analysis of fresh samples and samples exposed during impedance tests indicated a layer rich in oxygen over the ZrN coating after exposure but not over TiN coating. Chemical shifts in the Zr 3d5/2 core electrons indicate transformation from ZrN to its oxide; the shifts in Ti 2p3/2 did not support the change from TiN to its oxide. The influence of these shifts on corrosion protection is documented.

Subject
Steel surfaces, Coatings, Tin, Nitrides, Passive films, Impedance, Titanium oxide, Surface analysis, Film formation, Sputter deposition, Oxygen, Stainless steel, Samples
Keywords:
Tin, ZrN, ESCA, impedance, cyclic polarization, passive film
© 1994 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).
1994
Association for Materials Protection and Performance (AMPP)
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