Abstract: The cyclic voltammetry, convolution voltammetry, potentiostatic electrolysis and open circuit potential time curve after electrolysis, current time curve at potential step, potential time curve at current step, X ray diffraction, EDAX, electron probe microanalysis were used to investigate the electrode processes of the reduction of rare earth ions on inert electrodes and alloying electrodes in molten chlorides and fluorides. The free energies of formation for the intermetallic compounds, the diffusion coefficients of rare earth ions in the melt, the diffusion coefficients of rare earth atoms in the alloy phases were determined. The alloys of rare earth with iron, cobalt, nickel, copper, magnesium respectively were prepared by consumable cathode method and electrolytic codeposition method. Electrode processes of Fe 2+ , Co 2+ ,Ni 2+ reduced to Fe, Co, Ni respectively in urea melts were investigated. The transfer coefficients of the electrode reactions and the diffusion coefficients of the iron group ions in the melt were determined.The rare earth ions can′t be electroreducted to rare earth metals in urea melt, but can be inductively codeposited with iron goup metals to form rare earth iron group alloys.

Key words: Rare earth metals and their alloys, Molten salt, Electrodeposition, Kinetic parameters, Free energies of formation