Effects of Temperature, Ti(III) Ion Concentration, and Current Density on Electrodeposition of Ti Films in LiF-LiCl Melt

The effects of temperature, Ti(III) ion concentration, and current density on the electrodeposition of Ti films were investigated in the eutectic LiF-LiCl melt at 823-973 K. The Ti(III) ions were prepared by adding Li2TiF6 and Ti metal to the melt. The diffusion coefficients of Ti(III) were 1.4, 1.8, 2.3, and 3.2 x 10(-5) m(2) s(-1), at 823, 873, 923, and 973 K, respectively. Galvanostatic electrolysis was conducted at 823-973 K. The surface roughness (S (a)) of the Ti films decreases with decreasing temperature. Thus, the electrodeposition of Ti films was conducted at the lowest temperature of 823 K with various Li3TiF6 concentrations (0.55-7.1 mol%) and cathodic current densities (50-1200 mA cm(-2)). The S (a) was lower at higher Ti(III) ion concentrations and lower current densities. The smoothest Ti films with a S (a) of 1.23 mu m and a thickness of 10 mu m were obtained at a cathodic current density of 50 mA cm(-2) and Li3TiF6 concentration of 7.1 mol%.