Kinetics of current-enhanced dissolution of nickel in liquid aluminum

The dissolution kinetics of nickel in liquid aluminum at temperatures in the range 767–867 °C were investigated under the influence of a DC current. The current had a marked effect on the dissolution rate constant. Correspondingly, the application of the current significantly decreased the activation energy of dissolution. The direction of the DC current was shown to have an effect on dissolution. When the electronic flow was in the direction of dissolution, a further increase in dissolution was observed and attributed to electromigration. Calculations of the effective diffusion coefficient, Deff, of Ni through one of the two intermetallic layers, Al3Ni2, were made for different current densities and temperatures. From measured electromigration enhanced flux, the effective charge, z∗, on the diffusing Ni was calculated.