Effect of Microalloying with Ti or Cr on the Corrosion Behavior of Al-Ni-Y Amorphous Alloys

The effect of microalloying with Ti or Cr on the corrosion behavior of Al-Ni-Y amorphous alloys in 0.1 M NaCl solution was studied by potentiodynamic polarization, Mott-Schottky, and x-ray photoelectron spectroscopy techniques. Microalloying with Ti or Cr could greatly improve the corrosion resistance of Al-Ni-Y amorphous alloys. A high surface concentration of Ti or Cr in the passive films was detected, which should be responsible for the improved corrosion resistance compared to the control sample. The possible process of Ti or Cr involved in the passive films was proposed in terms of the point defect model and the vacancy diffusion mechanism. Furthermore, the effect of Ti was stronger than Cr because of the higher film resistance as well as the higher surface concentration. The different passivation abilities and atomic radiuses between Ti and Cr were presented to explain the better microalloying effect of Ti compared to Cr.