Pre-treatment processes for automotive applications in Europe are optimised firstly due to the increasing use of aluminum and coated steel for car bodies and parts and secondly due to environmental issues. Prephosphated coated steel, mainly electrogalvanised steel with a trication zinc phosphate layer applied in the steel mill is used by many car manufacturers. Several R&D projects are under way to coat aluminum sheet with inorganic or organic layers to enhance forming, welding and joining properties. Environmental aspects initiated the development of cleaners with biodegradable and alkylphenolethoxylate-free surfactants, liquid grain refiners with longer bath life-time, nickel or nitrite-free zinc phosphate products and chrome-free passivations. All of these products are in use in many automotive body lines except the nickel-free phosphating process which is being tested in OEM parts lines. Details of the processes in a phosphating line are described including a section on phosphating of aluminum.

Subject
Zinc nickel coatings, Coated steel, Zinc rich coatings, Materials, Manufacturing, Aluminum, Research and development, Pretreatment, Steel, Automotive, Zinc, Paints, Phosphating
Keywords:
prephosphated coated steel, precoated aluminum, liquid grain refiners, nitrite-free zinc phosphating, nickel-free zinc phosphating, chrome-free passivation
© 1995 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).
1995
Association for Materials Protection and Performance (AMPP)
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