Effects of mechanical deformation on the protection properties of coil coating products

The possibility of introducing some defects in shaping and forming metal sh eets can decrease the performance of coil coatings products, reducing the a dvantages of this technology, which is relevant from an economical and envi ronmental point of view. In this work are studied different coating product s, containing environmentally friendly pigments (Ion Exchange Pigments), de formed atlons: bending and deep drawing. After the calculation of the strai n induced by deformation, the samples were characterised by Electrochemical Impedance Spectroscopy in order to study the protective properties of orga nic coatings as a function of the imposed deformation. It was possible to c ompare the different coating cycles and to identify a maximum acceptable st rain threshold for every material. In order to optimise the experimental ap proach, the data obtained using different deformation methods, but with a s imilar strain were compared, showing that the deep drawing deformation (cup ping test) seems to be the simplest and the most useful way for an electroc hemical characterisation of organic coated metal sheets after mechanical de formation. (C) 2000 Elsevier Science Ltd. All rights reserved.