Technical note Evidence of dissolution-redeposition mechanism in activation of aluminium by indium

Electrochemical impedance spectroscopy, scanning electron microscopy, and energy dispersive X-ray analysis were employed to provide evidence of the dissolution and redeposition steps involved in the activation of aluminium by indium in aluminium alloy sacrificial anodes having indium as an activator. The experiments clearly showed that the alloyed indium dissolved and redeposited back on to the aluminium surface. This redeposition step was responsible for activating passive aluminium.