The delamination of polymeric coatings from electrogalvanised steel -: a mechanistic approach.: Part 1:: delamination from a defect with intact zinc layer

The basic mechanism of the cathodic delamination of polymer films from zinc-coated steel starting from a defect with an intact zinc layer has been derived. Scanning Kelvinprobe and ESCA measurements have been carried out with a very simple model system. The delamination is presented as the formation of a galvanic element between the active defect and the delamination front with electrons and cations being transported to the local cathode. The oxygen reduction in the delaminated area leads to an alkalinisation of the zinc/polymer interface resulting in a significant growth of the oxide layer. (C) 2001 Elsevier Science Ltd. All rights reserved.