Corrosion Process of Acrylic Polyurethane Coatings in Yangtze River Water

The failure process of acrylic polyurethane coatings in Yangtze River water sample was studied by EIS. The results show that the diffusion process of water incoating presents two typical stages, the linear increased stage and slow increased stage. According to the linear part of lnCc-t1/2 period, the water diffusion coefficient D was obtained and the value is 6.78×10-10 cm2/s which is almost the same with the water diffusion coefficient D in coastal atmospheric condition. The failure time of the coating was up to 700 h, much longer than that in coastal atmospheric condition, and it is proved to be a kind of good coating.