关键词: 5083铝合金, 耐蚀性, 电解质效应, 海水环境

Abstract: The interaction effects of typical anions, namely, Cl^-, HCO₃^- and SO₄^2-, presented in seawater environments on corrosion resistance behaviors of AA5083 aluminum alloy have been studied. The corrosion resistances of the 5083 aluminum alloy in different simulated seawater environments were tested by factorial analysis method. The polarization curves, the corrosion potentials, corrosion current densities and the breakdown potentials were examined in different concentrations of Cl^-, HCO₃^- and SO₄^2-.The corrosion behavior was analyzed by electrochemical impedance spectroscopy (EIS). The results showed that both Cl^-,  and HCO₃^- could accelerate the pitting corrosion. When the concentration of Cl^-,  remained constant, the corrosion resistance of AA5083 aluminum alloy increased initially with an increase in the concentration of HCO₃^-,and then dropped dramatically at 70～90 mg•L^-1, which displayed the best corrosion resistance performance. Afterwards, the corrosion resistance increased again. The corrosion current density of AA5083 aluminum alloy was not significantly affected by SO₄^2- when the concentrations of Cl^- and HCO₃^- became larger. Meanwhile, when the concentration of HCO₃^- was fixed, the charge-transfer resistance of AA5083 aluminum alloy at a lower Cl^-concentration was smaller than that at a higher Cl^- concentration, and the corrosive ions could easily penetrate the native oxide film by a redox reaction with the matrix.

Key words: 5083 aluminum alloy, corrosion resistance, electrolyte effect, seawater environment