Self-stratifying coatings containing barrier and active anticorrosive pigments

The influence of decorative and anticorrosive pigments on the distribution of pigments and protective properties of self-stratifying epoxy/acrylic coating systems was investigated. The separation of pigments was determined basing on their properties and the type of additives used and was expressed as a factor determining the separation of the pigments between the upper and bottom layer. The pigment distribution coefficient was calculated basing on the colour difference between the upper and bottom layer as well as by means of the XRF method. The results of investigations of self-stratifying coatings in a salt spray chamber prove that such systems have comparable or even better corrosion protection properties compared to classical two-layered systems containing the same resins and pigments. The best adhesion to substrate, interlayer cohesion and pigment distribution were obtained in systems containing chrome oxide green and micaceous iron oxide. (C) 2011 Elsevier B.V. All rights reserved.