Direct preparation of V-Al alloy by molten salt electrolysis of soluble NaVO₃ on a liquid Al cathode

Vanadium-aluminum (V-Al) alloy, the master alloy for the well-known Ti-6Al-4V alloy, is mainly produced via aluminothermic reduction process of V₂O₅ over the past decades. However, the reaction rate is too fast and it is difficult to control the product quality. Moreover, the utilization of aluminum is very low due to the production of Al₂O₃. In this work, a new method is proposed to prepare V-Al alloys by molten salt electrolysis of soluble NaVO₃ on a liquid aluminum (Al) cathode in molten NaCl-KCl melt. The results show that VO₃⁻ ions can be reduced to metallic V-Al alloys on the liquid Al cathode during electrolysis process. Furthermore, thermodynamic and electrochemical analysis indicate that the reduction of VO₃⁻ ions on the liquid Al cathode results from the combined effect of electroreduction and aluminothermic reduction. In this process, the liquid Al can not only reduce VO₃⁻ ions to V, but also to combine with vanadium to form V-Al alloys. However, unlike the traditional aluminothermic reduction process, alumina produced due to the aluminothermic reduction will be in-situ electro-reduced to aluminum, which will be helpful to increase the utilization of aluminum. As a result, when the electrolysis voltage is enough large, VO₃⁻ ions will be completely reduced. Al₃V alloy without alumina can be obtained.