Study of the formation of β-lial alloy by electrochemical techniques in molten LiCl+KCl

The formation of β-LiAl during electrochemical incorporation of lithium into α-LiAl alloy from molten LiCl+KCl was investigated by chronoamperometric and chronopotentiometric techniques. It is shown that at the very beginning of the lithium incorporation a supersaturation of the α-phase occurs, the incorporation being controlled by the metal diffusion in the β-phase.The initial stages of formation of β-LiAl are explained in terms of a model involving nucleation and three-dimensional growth. In contrast with the model for conventional electrolytical metal deposition the process is controlled in the first moment by the lithium/aluminium interdiffusion in the growing β-nuclei. However according to the high value of the interdiffusion coefficient the process is rapidly limited by the ohmic resistance of the circuit.