Determining the effect of environmental conditions on iron corrosion by atomic absorption

Iron corrosion is a complex process that occurs when iron is exposed to oxygen and humidity and is exacerbated by the presence of chloride ions. The deterioration of iron structures or other components can be costly to society and is usually evaluated by following the properties of the corroding material. Here, the iron ions released into solution due to corrosion were detected directly by atomic absorption and their concentration was determined using a calibration curve. Iron corrosion was measured in samples immersed in aqueous solutions that differed in salinity (increasing NaCl concentrations), pH, temperature and presence of oxygen, and under the cathodic protection of a zinc ingot. The corrosion of the iron samples in solution was accelerated by high salinity and temperatures, low pH, the presence of chloride ions and oxygen, and the absence of cathodic protection. Material deterioration due to exposure may be arrested or enhanced by understanding the conditions that expedite the reactions. The experiment was performed by third-year material engineering students and would also be appropriate for an upper-level analytical lab.