Interface electrochemical corrosion behaviour of alclad Al–Zn–Mg–Cu–Cr Al alloy adhesively bonded with carbon fibre reinforced plastic stiffener

AbstractStiffening of Al alloy aircraft structures with carbon fibre reinforced plastic laminate called ‘patches’ is considered as a viable option to enhance fatigue life. Interface so created between the reinforcement and Al alloy structure is potential site for crevice corrosion attack. Therefore, studies were conducted to investigate the interface corrosion behaviour of peak and two-step aged Al–Zn–Mg–Cu–Cr alclad alloy with and without the patch and examine the possibility to control the interfacial attack with the addition of cerium chloride inhibitor exposed to 3·5 wt-% NaCl solution for the durations of 2 and 168 h. Electrochemical impedance spectroscopy revealed that the interface attack was significantly reduced by the addition of 1000 ppm cerium chloride. The response of the peak and two-step aged alloy for such an addition was further investigated and found that the alloy under step aged condition behaves better than that of the peak aged condition.