1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha, 410083, China; 2. AECC South Industry Co., Ltd, Zhuzhou 412002, China; 3. Zunyi Titanium Co., Ltd, Zunyi, 563004, China
Abstract：Sodium chloride and potassium chloride were used as molten salt, and sponge titanium cathode was purified by molten salt electrolysis. According to the theoretical deduction of nucleation rate in the electrolysis process, the effects of electrolysis temperature and different proportion of molten salt on the crystal morphology of high purity titanium were analyzed, and the crystallization mechanism in the electrolysis process was studied. The results show that the size of crystalline Ti particles gradually increases with the increase of electrolytic temperature, and the crystalline particles gradually change from long strip or elliptic to dendritic. The increase of KCl content in molten salt will lead to the increase of molten salt resistance and the decrease of current efficiency, resulting in the decrease of crystalline Ti particle size, the loose of crystalline Ti and high salt inclusion rate. The microscopic characterization of crystalline Ti particles revealed that during the molten salt electrolysis process, the titanium crystals grew in steps, corresponding to two-dimensional nucleation. The electrolytic titanium powder is not a single crystal, but a polycrystal containing many nanocrystals and subcrystals, with a grain size range of 100-500 nm.
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2020, Vol. 25 
