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The electrochemical impedance technique was employed to study the corrosion of two-phase Cu-15Al alloy in molten (0.62Li, 0.38K)(2)CO3 at 650degreesC in air. The results indicate that the corrosion of the alloy goes through two stages. In initial stage, the corrosion of the alloy shows typical features of a diffusion-controlled reaction. With extended immersion, the Nyquist plots are composed of a large capacitive loop at low frequency, a line at intermediate frequency and a small semicircle at high frequency, which is related to the formation of a protective Al2O3 scale. Two impedance models were proposed to describe the corrosion of the alloy. (C) 2003 Elsevier Ltd. All rights reserved.