Organic and Inorganic Coatings for Corrosion Prevention - Research and Experiences (EFC 20) PDF

Preface

The environment at the present time is becoming more and more aggressive with respect to artefacts. The protection of building structures, high voltage towers, offshore constructions, bridges, chemical plants, electrical equipment and even art objects, monuments etc. is almost always achieved by means of the best method available to separate the object from the environment, i.e.the application of a coating.

Apart from aesthetic considerations, the use of protective coatings is receiving significant attention both in the scientific and in the marketing fields, being driven, on the one hand by the increasing demand for total quality, outstanding performance, long and reliable service life, and on the other hand, by the need for low prices, easier application techniques and environmentally friendly components.

Most coatings are multilayer systems and include a metal layer (zinc, aluminium or other metals or alloys), a chemical pretreatment (phosphate layers and/ or adhesion promoters), a set of organic (polymer) layers (primer, intermediate, top-coat) each one characterised by specific duties and related features and components. Moreover, many of the commonly used dangerous components (chromium, lead, organic solvents, cadmium, ... ) are no longer acceptable in environmental awareness terms, although their performances are acknowledged to be outstanding. There is a need for substitutes (or alternative techniques) with both comparably reliable performances and environmental accetability.

In the session on Coatings held during EUROCORR' 96the following topics were much discussed:

• Life-time prediction of organic coatings;
• Environmentally friendly coatings;
• Testing; and
• Surface preparation techniques.

This book contains a selection of the scientific work presented in the Conference with the aim of focusing on the research developments in the frame of corrosion protection coatings for industrial use.

The book is in four sections describing, respectively, organic coatings, zinc coatings, other metallic coatings and ceramic coatings.

Electrochemical techniques such as Electrochemical Impedance Spectroscopy (EIS)or Electrochemical Noise Analysis proved to be very effective in the testing of organic coatings. Attention was also paid to metal surface preparation and to coating adhesion.

Ceramic coatings including oxides and nitrides produced using spraying or physical vapour deposition techniques, were studied in various aggressive environments, with care taken to obtain corrosion resistance data in conditions of mechano-chemical attack (wear-corrosion, erosion corrosion).

Surface modification by laser treatments is described in some detail.

Various metal deposition techniques are described - including hot-dip, electrodeposition, spray or sol-gel - for the production of corrosion resistant coatings of nickel, aluminium or zinc alloy.

Edited by: L. Fedrizzi, P.L. Bonora