Galvanic corrosion of aluminium–copper model alloys

Galvanic coupling between different α and θ phase-containing model Al–Cu alloys, deposited by magnetron sputtering, has revealed that the anodic α phase did not suffer corrosion and remained in the passive state in sulphate solution. Conversely, sulphate ions induced pitting of the cathodic θ phase. Pitting susceptibility of the cathode increased when the difference between the copper content of the anode and cathode increased. Similar observations were made for all the galvanic couples; further, the higher the copper content of a phase, then the greater its susceptibility to pitting.