Influences of In<sup>3+</sup> and Ga<sup>3+</sup> on the Electrochemical Behaviour of Al in KOH Solution

Electrochemical behaviors of Al in 1 mol.L-1 KOH solution without and with the addition of In3+ or Ga3+ were investigated with potentiodynamic polarization and EIS techniques. Corrosion rates were measured by volumes of hydrogen evolved. The results show that though indium and gallium are the metals with high H-2-evolution voltage, addition of Iu(3+) retards both anodic and cathodic reaction of the corrosion of Al in KOH solution and thus inhibits the corrosion. while Ga3+ accelerates the anodic dissolution process as well as the corrosion of Al in the solution. SEM verified the above results.