THE STABILITY OF THE PASSIVE STATE ON AL-MO SPUTTER-DEPOSITED GLASSY METALS

The anodic behavior of sputter-deposited Al-Mo glassy alloys containin g 15-45 at% of Mo were investigated in 0.05-1 M NaCl by using electroc hemical, microscopic and surface analytical methods. The alloys exhibi ted a stable passivity within a large potential region. AES revealed t he presence of oxidized Al, Mo and O within the passivating film. The alloys underwent pitting at and above an anodic potential, which was a bout 1200 mV higher than the corresponding pitting potential for Al me tal. The pitting potential for Al-Mo glasses increased by approximatel y 200 mV with a 10 at% increase in Mo content and decreased by approxi mately 50 mV with a ten-fold increase in chloride concentration in the electrolyte. A tentative mechanism of pit nucleation in Al-Mo glasses is discussed.