Author : Ahmed A. Atshan , Basim O. Hasan and Mohammed H.Ali

The effects of different parameters and conditions on the impressed current cathodic protection of steel structure in 3% NaCl solution were investigated using both weight loss method and electrochemical polarization technique. The effect of anode type, anode to cathode distance, anode to cathode area ratio, temperature, and time on the effectiveness of cathodic protection was studied and discussed. Graphite and scrap iron of various lengths were used as impressed current anodes. These were placed at different distances from structure (cathode) and different values of protection currents and potentials were applied and effects of time and solution temperature were studied. The results revealed that the scrap iron provides more economical protection than graphite, corrosion rate was decreased as the applied current increased when scrap iron was used. Increasing distance between anode and cathode leads to a decrease in the protection efficiency. The lower the area ratio of cathode to anode, the better the protection against corrosion. Generally, the protection potential shifts to more positive after short time from applying the protection. However, the protection current decreases appreciably with time in a manner depending on anode type and solution temperature which affects both protection potential and protection current.

Keywords: Cathodic protection, Steel structure etc.

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.5(Dec- 2013)