Influence of NaCl deposition on Atmospheric Corrosion of Carbon Steel

Atmospheric corrosion can be defined as the corrosion of materials exposed to air and its pollutants rather than immersed in a liquid. Regularity of the initial atmospheric corrosion of carbon steel in the presence of NaCl was investigated. The result shows that Sodium Chloride (NaCl) can accelerate the corrosion of carbon steel. Dry mass gain of carbon steel in the presence of NaCl increases with exposure of time, which can be correlated by using experimental decay function. The relation of dry mass gain and amount of NaCl deposition at certain time follows a quadratic function. More amount of NaCl deposition would slow down the corrosion rate to some extent after exposure for a certain time. The experiment was conducted to measure the corrosion rate of the metal which was exposed to the environment of different concentration (%) of NaCl. The exposure time was set to four weeks for each concentration and the data was analyzed. The data was gathered in a table and graph was plotted to show the relationship of the NaCl deposition on the sample. From the analysis, the results show that the NaCl deposition increased with the increasing of exposure time. This is because of the electrochemical process that takes places on the surface of the carbon steel.