Corrosion behaviour of Al-29at%Co alloy in aqueous NaCl

Microstructure and corrosion behaviour of a binary Al-29 at%Co alloy have been studied. The alloy was prepared by arc-melting of Al and Co in high purity Ar and rapidly solidified on a water-cooled Cu mould. The alloy chemical composition and microstructure were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Furthermore, the corrosion behaviour was studied by potentiodynamic polarization in aqueous NaCl (0.6 mol dm−3) at room temperature. The alloy was found to consist of three phases: hexagonal Al5Co2, Z-phase and AlCo (β). The corrosion resistance of different intermetallic phases is characterized. The results are compared to previously published results of Al-TM (TM = transition metal) alloys.