A laboratory accelerated test set-up was built to simulate the environment of the coastal saline soils at Tianjin coastal area. Corrosion performance of three typical materials for water supply pipes such as ductile iron, grey cast iron and carbon steel, was assessed by means of weight loss method and electrochemical measurement. The main conclusions are as follows: the three materials present more or less the same corrosion tendency in the test environment. The corrosion process can be differentiated into three stages: pitting induction stage, pitting developmental stage, and stable corrosion stage. The charge transfer was the control step in the initial- and middle-stage of corrosion, while the charge transfer resistance rose rapidly as the corrosion proceeded, however, the oxygen diffusion became the controlling step for the stable corrosion stage. The polarization curves of three materials showed obvious double control of cathodic diffusion and anodic activation, and the cathode diffusion control was more obvious.
Corrosion Science and Protection Technology
coastal saline soil
grey cast iron