Microstructural evolution during the dissolution of nickel in liquid aluminum under the influence of an electric field

The influence of a DC current on the microstructural evolution of phases resulting from the dissolution of solid Ni in pure and Ni-saturated liquid Al was investigated. Experiments were carried out with the dissolution flux and the electronic flow being co-linear and counter-linear. The change in microstructure in the presence of a current, and its dependence on current density, is consistent with an increased dissolution of the Ni in liquid Al. No dissolution of Ni in Ni-saturated liquid Al was observed in the absence of current, but is significant when a current is imposed. On the surface of the Ni, two intermetallics formed: Al3Ni2 and Al3Ni. The former grew parabolically during dissolution in the absence of a current, but remained constant when a current was imposed. The calculated effective diffusion coefficient decreased with dissolution time, indicating a reduction in dissolution rate with increasing concentration of dissolved Ni.