Corrosion-resistant amorphous aluminum alloys and structure of passive films

The corrosion behavior of amorphous Al-Ti-Ni, Al-Cr-Ti and Al-Cr-Mo alloys in 1 M HCl and that of amorphous Al-Ti-Mg alloys in chloride containing neutral solution is investigated. The amorphous Al-Ti-Ni, Al-Ti-Cr and Al-Cr-Mo alloys are passivated spontaneously even in 1 M HCl and show lower corrosion rates and higher pitting potentials in comparison with Al-Ti and Al-Cr binary alloys. Al-Ti-Mg alloys containing relatively low concentration of magnesium possess a better resistance against pitting corrosion. X-ray photoelectron spectroscopy measurement reveals that titanium and chromium are enriched in the passive films formed on Al-Ti-Ni, Al-Ti-Mg and Al-Cr-Mo alloys, respectively. Angle-resolved XPS measurements were performed in order to characterize the in-depth distribution of constituents in the passive films formed on amorphous Al-Ti-Ni, Al-Ti-Mg and Al-Cr-Mo alloys in the passive films of which, passivating elements are enriched.