Effect of Zinc Rich Paints on the Durability of Epoxy Top Coats in Sodium Chloride Solution

Hiroyuki Tanabe, Toshio Shinohara, Yasushi Sato, Hiroshi Nii, Minoru Hoshino, Keisuke Itami
1981 Corrosion engineering digest  
Effect of inorganic zinc rich paints on the durability of epoxy top coat was investigated in 3 wt % sodium chloride solution. It was found that paint failure of epoxy top coat such as blisters was predicted by polarization resistance measurement, impedance measurement, electrode potential measurement of the coated mild steel. The coated mild steel which had no failure for 400 days hold high polarization resistance over the same period. The coated steel also kept a initial value of high
more » ... ue of high impedance. The same sample showed only a slight shift of electrode potential toward the less noble direction. Epoxy top coat over zinc rich paints had no failure after 400 day service and the system was superior to the epoxy top coat which was directly applied to the blasted steel. As a conclusion, the coating system that epoxy top coat was applied to zinc rich paint-coated steel showed the most excellent durability in 3 wt % sodium chloride solution, evaluating from electrochemical measurements and the result coincided with the observation of the test panels.
doi:10.3323/jcorr1974.30.7_390 fatcat:qecgmeerunfepecxrzr2nr6j64