Impedance measurements of polyester-coated galvanised mild steel in 10xacid rainwater after an accelerated wet-dry test

The variation of defective polyester-coated performance with time in 10xaci d rain solution was investigated using electrochemical impedance spectrosco py. Measurements were carried out on samples after an accelerated atmospher ic corrosion test. The impedance diagrams (Nyquist plots) were simulated us ing the EQUIVCRT program which was elaborated by Boukamp and the semi-ellip se model which was developed by Erbil. It has been shown that the defective coating resistance changes with time for the samples subjected to acid rai nwater. The corrosion rate of coated metal also changes with time.