The Effect of Industrial and Marine Industrial Atmospheres on Performance of Zinc Rich Epoxy and Zinc Ethyl Silicate Coating Systems

In this study, the influences of thickness on the weathering performance of coating systems including zinc rich epoxy or ethyl silicate primer, epoxy/polyamide surfacer and polyurethane topcoat were investigated. Natural weathering was evaluated in Arak in center of Iran and Mahshahr located near Persian Gulf. The results showed that gloss retention of the systems exposed to Arak was higher and there was a relatively low variation in yellowness index of the systems that can be attributed to gradual surface erosion. Surface erosion, postcuring and photodegradation of the topcoat also caused a fluctuating variation in hardness of the systems. In addition, the results presented that 800 hours accelerated weathering was equal to 7 months natural weathering in Mahshahr. It was also found that an increase in thickness increased cyclic corrosion resistance of the epoxy systems, while, no defects were detected on surface of all the systems during salt spray and natural weathering. J. Color Sci. Tech. 8(2014), 59-74©. Institute for Color Science and Technology.