Effect of Concentration and Exposure Time on Mild Steel Corrosion in Sodium Chloride

One of the major aspects in terms of cost and security of both industrial and marine environments is corrosion. This paper is an experimental study of the corrosion behavior of mild steel in sodium chloride at various concentrations (0.5 -10 wt. %) after 168 hours. The methods used were in visual analysis and microscopy. It was established that corrosion rate increased with concentration of NaCl but deviated at higher concentrations. The mass loss versus time was almost linear in a graphical representation and the rate of corrosion versus concentration exhibited a maximum level. These findings are related to the electrochemical concepts of oxygen diffusion and formation of corrosion products, which are explained. Highest corrosion risk is determined and recommendations made concerning the best concentration which presents maximum corrosion risks and protective measures are recommended to the marine structures.