Electroless nickel coated connectors exhibited plating failures after time in storage only, prior to any use. The subsequent investigation and failure analysis identified several types of problems. The plating sequence, operations, and bath were found to contribute significantly to the plating failures. In addition, the galvanic potential between aluminum and nickel causes severe deterioration of the aluminum substrate where any perforation of the electroless nickel coating is experienced.

The testing methods used to determine environmental resistance of military parts have been questioned. (1) A test method is proposed which may provide better correlation with specified environmental exposures.

Alternate materials and coatings have been suggested, and limited testing is presently in progress. No single alternative system yet proposed appears to be satisfactory for all the uses to which electroless nickel coated parts are subjected. Corrosion resistant steel parts inflict a weight penalty, while cadmium coated aluminum parts are not suitable for high temperature or high vacuum (space environment) applications. In addition, Electromagnetic Interference (EMI), Electromagnetic Pulse (EMP) and Radio Frequency (RF) requirements must be considered during part design and coating selection. Current guidelines stress use of electroless nickel coated aluminum where EMI, EMP and RF requirements are design drivers.

It has long been recognized by corrosion engineers that nickel is not a good choice if one wants to protect aluminum from corrosion. It is interesting that most design engineers were unaware of the effects of a noble metal coating on an active basis metal. Corrosion engineers must take the task of educating those who are unfamiliar with the chemical and corrosion properties of materials.

Subject
Nickel coatings, Test methods, Materials, Plating, Aluminum, Hardware, Photomicrographs, Magnification, Phosphorus, Salt spray corrosion testing, Engineers, Nickel, Electroless nickel
© 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)
You do not currently have access to this content.