抄録
In this work, the influence of cation species on the corrosion behavior of Al–Mg–Si alloy in Cl- containing solution was studied by immersion test and electrochemical measurement. The results of immersion test showed that severe pitting corrosion occurred at the Al-masking boundary of the sample and more weight loss of samples after immersion test gained in MgCl2 solution than those in NaCl and CaCl2 solutions. Anodic polarization curves showed little difference in pitting potential of Al–Mg–Si alloy in Cl- containing solutions regardless of the cation species. On the other hand, cathodic polarization curves showed the increase of cathodic current density in MgCl2 solution than those in NaCl and CaCl2 solutions. This electrochemical behavior suggested the remarkable corrosion of Al–Mg–Si alloy in MgCl2 solution was caused by the increase of cathodic reaction. The reason why the cathodic reaction increased in MgCl2 solution was considered that the pH at cathode surface was kept by buffering action of Mg2+ because of the less solubility of Mg (OH) 2.
