Institute for Color Science and Technology (ICST) Progress in Color, Colorants and Coatings 2008-2134 15 1 2022 02 01 Investigation of Corrosion Properties of Modified Epoxy and Polyurethane Organic Coating on Steel Substrate 25 36 81741 10.30509/pccc.2021.166736.1092 EN M. Mirzaee University of Tehran, Faculty of Engineering, School of Metallurgy and Materials Engineering, Tehran, Iran. M. Rezaei Abadchi Non-metallic Materials Research Group, Niroo Research Institute, Tehran, Iran. A. Fateh Department of Materials Engineering, Tarbiat Modares University, Tehran, Iran. A. Zolriasatein Non-metallic Materials Research Group, Niroo Research Institute, Tehran, Iran. Journal Article 2020 10 25 <em>In this study, the organic coating of epoxy zinc-chromate (E) and the two-layer coating of epoxy zinc-chromate-polyurethane (PU-E) was coated on the steel substrate using the spraying method. Then, their corrosion resistance was compared using electrochemical impedance spectroscopy (EIS) and dynamic polarization tests. Comparison of corrosion properties using parameters of, phase angle at a maximum frequency (100kHz), and breakpoint frequency (f<sub>b</sub>) were performed during 2, 4, and 8 weeks. A comparison of these three parameters showed that the corrosion resistance of the PU-E coating was higher than the E coating due to the behavior of the polyurethane coating barrier as well as the active protective behavior induced by the chromate pigments which was distributed on the epoxy coating. According to the test results, E and PU-E coatings had good hardness and scratch resistance and were resistant to pencil scratches with H and F hardness, respectively. The salt spray test for the two-layer coating showed no qualitative change, damaged area, blistering/delamination, or corrosion products on the coated sample. The results showed that both coatings were suitable candidates for use in various industries, including marine and power industries, and other industries that suffered from corrosion problems.</em> Epoxy Polyurethane Zinc-chromate Corrosion Resistance https://pccc.icrc.ac.ir/article_81741_5a9b0ce1e44cef228834e10d4f8fbb63.pdf