Facile Electrodeposition of Ti 5 Si 3 Films from Oxide Precursors in Molten CaCl 2

It is hard to produce dense refractory Ti 5 Si 3 films at low temperature because of the extremely high melting point (2130 °C) of Ti 5 Si 3 . Herein, we report the facile electrodeposition of Ti 5 Si 3 films from TiO 2 and SiO 2 in molten CaCl 2 -CaO at 850 °C. Crystalline Ti 5 Si 3 films with tunable film thicknesses and morphologies can be obtained in a controlled manner. The dissolution-electrodeposition processes were systematically investigated by cyclic voltammetry (CV), in-situ X-ray diffraction (XRD), in-situ Raman analysis, etc. , and the synthesized Ti 5 Si 3 products were characterized by electron backscattered diffraction (EBSD), transmission electron microscopy (TEM), three-dimensional atomic probe (3DAP), etc . The results show that the morphology of the products can be significantly influenced by current density. By controlling current density at the range from 10 to 25 mA cm −2 , Ti 5 Si 3 products with different morphologies, i.e. , dendritic particles, dense films, and porous powders, can be obtained in a controlled manner. Besides, Ti, Si atoms uniformly distributed in the films. The reaction mechanism of the formation of Ti 5 Si 3 film was also proposed, which can be summarized as three periods: CaO-assisted dissolution of SiO 2 and TiO 2 , the electrodeposition of Si and Ti, and the formation of stable Ti 5 Si 3 phase. The CaO-assisted dissolution-electrodeposition process may provide a promising strategy for the production of Ti 5 Si 3 alloy films and powders.