ELECTRODEPOSITION FROM MOLTEN-SALT UNDER DIRECT MAGNETIC-FIELD APPLICATION

The effect of a direct magnetic field on the solid phase deposition of aluminum has been studied by using the molten salt of 2AlCl3-NaCl wit h addition of 5 mass% MnCl2. In the weak magnetic field range natural convection predominates the mass transfer rate of deposition and in th e strong magnetic field range electromagnetic force controls the mass transfer rate and increases the critical current density to keep the d eposition surface bright and smooth. Based on the boundary layer theor y taking account of the electromagnetic force the analytical expressio n of the mass transfer rate has been derived. The theoretical result p redicts the critical current density is proportional to one third powe r of the magnetic flux density and is confirmed by the experimental re sults.