Exfoliation corrosion susceptibility of 8090 Al-Li alloy examined by electrochemical impedance spectroscopy

来源期刊：中国有色金属学报(英文版)2004年第4期

论文作者：蔡超 李劲风 郑子樵 张昭

文章页码：742 - 746

Key words：exfoliation corrosion; 8090 Al-Li alloy; electrochemical impedance spectroscopy(EIS)

Abstract: The exfoliation corrosion susceptibility and electrochemical impedance Spectros copy(EIS) of rolled and peak aged 8090 Al-Li alloys in EXCO solution were studied, and the EIS after exfoliation was simulated. Once exfoliation occurs, two capacitive arcs appear in the EIS at high-mediate frequency and mediate-low frequency respectively. The exfoliation-attacked alloy surface consists of two parts, an original flat alloy surface and a new inter-face exposed to EXCO solution due to the exfoliation. The capacitance corresponding to the new exfoliation inter-face increases approximately linearly with time at early exfoliation stage, due to the enlargement of the new inter-face. Then it maintains stable, due to the corrosion product covering on the new inter-face. The exfoliation susceptibility can be judged through the average slope of the capacitance vs time curve of the early exfoliation stage. This average slope of the rolled 8090 alloy is much higher than that of the peak-aged 8090 alloy, accordingly the rolled 8090 alloy is more susceptible to exfoliation than the peak-aged 8090 alloy.