Influence of temperature on the reduction mechanism of Ti(III) ions on iron in the LiF-NaF-KF eutectic melt and on the electrochemical behavior of the resultant titanium coatings

The electroreduction mechanism of Ti(III) ions on iron in the LiF-NaF-KF eutectic melt was studied at 700 and 900degreesC using cyclic voltammetry. At both temperatures, the reduction occurs through a three-electron transfer, but at 700degreesC only pure titanium is deposited, whereas the successive formation of Fe2Ti and FeTi intermetallic compounds precedes pure titanium deposition at 900degreesC. At 900degreesC under open-circuit conditions, the different phases appear successively at the electrode/electrolyte interface by interphase movements due to intermetallic diffusion. At the same temperature but under anodic polarization, each phase appears at the electrode surface according to a layer-by-layer dissolution. (C) 2004 Elsevier B.V. All rights reserved.