Preparation of low-oxygen Ti powder from TiO2 through combining self-propagating high temperature synthesis and electrodeoxidation

An effective method was reported to prepare low-oxygen Ti powder, which included two experimental steps: the fast conversion of TiO₂ to TiO_x<1 powder by self-propagating high-temperature synthesis (SHS) process and the generation of low-oxygen Ti powder by electrodeoxidizing TiO_x<1 powder at the cathode in molten CaCl₂. The key intermediate steps were analyzed by XRD, SEM and electrochemical testing techniques. The results demonstrated that TiO_x<1 powder (TiO_0.325 and TiO_0.97) was generated after acid leaching MgO in SHS products with TiO₂/Mg molar ratio of 1:2, and the TiO_x<1 powder with 16.3 wt.% oxygen could be transformed into pure titanium powder with 0.121 wt.% oxygen by electrodeoxidation at a constant potential of -3.3 V for 10 h. The electrodeoxidation of TiO_x<1 powder in CaCl₂ molten salt follows the step-by-step deoxidation mode, and the lattice of TiO_x<1 powder after electrodeoxidation shrinks.