Study of Coatings Applied on Zinc Surface

C. R. TOMACHUK; A. R. DI SARLI

British Journal of Engineering and Technology

British Association of Academic Research

Lugar: Nueva York; Año: 2012 vol. 1 p. 78 - 96

2326-425X

Recent European regulations for emissions of volatile organic compounds aim to substitute traditional resins by new pollution free products. In this work, the protective properties of novel water-based no-rinse products were addressed.Acrylic and epoxyphenolic no-rinse resins, compatible with the recent volatile product emission norms, were applied on electrogalvanised steel sheets previously subjected to a pre-treatment with and without Cr6+. Their electrochemical behavior in 0.3 M Na2SO4 solution, pH 10,was investigated by EIS. DSC was used to optimize the curing cycle, residual solvent content and coatings curing degree. The results showed that, independently of the applied conversion treatment, the epoxyphenolic film exhibited the best corrosion protective properties. EIS measurements were able to follow the evolution of the corrosive process as a function of immersion time, allowing identified phenomena, like some incompatibilities of the coating system with the substrate pre-treatment, otherwise indistinguishable. One of the investigated substrate-coating group presented similar performance than the displayed by the chromate pre-treated samples.