알루미늄의 부식에 미치는 Na2S, CuCl2, NaCl 농도의 영향

Abstract

A1100 is a pure aluminum with a purity of 99.0% or more and is an industrial material with excellent corrosion resistance and excellent machinability and thermal conductivity. Aluminum quickly corrodes in strong acids and strong bases but is highy resistant to corrosion environments with pH 4-9. However, the passive film of aluminum is prone to breakdown in the presence of aggressive ions such as Cl-, causing localized corrosion like pitting corrosion. In addition, aluminum is susceptible to galvanic corrosion in contact with metals such as Fe and Cu since the corrosion potential is lower than that of other metals. SOX in the atmosphere is known to promote the corrosion , but SO42-, a sulfate, can facilitate the passivation of aluminum. In this study, the corrosion behavior of aluminum in the aqueous solution containing Na2S, CuCl2, and NaCl was carried out, and the corrosion potential, corrosion rate, and pitting potential were measured. The main effect and the interactions between theions on the corrosio parameters were investigated by using the statistical analysis, based on the Responses Surface Methodology of DOE (Design and Experiment). As a result, the effect of Cu2+ ions on Ecorr was greatest, raising the Ecorr. In the case of Icorr, the three ions contributed slightly to the increase of Icorr. Epit was affected most significantly by Cl- concentration . The effect of S2- on the corrosion Ecorr, icorr, and Epit was small, but the increment of Epit by Cu2+ concentration was higher in the solution with more Na2S .