熔盐电解高纯钛的结晶机理及形貌  

Crystallization mechanism and morphology of high purity titanium prepared by molten salt electrolysis

作　　者：冯啸 姜嫄嫄 马鑫 翁启钢[3] 袁铁锤[1] 周志辉[1] FENG Xiao;JIANG Yuanyuan;MA Xin;WENG Qigang;YUAN Tiechui;ZHOU Zhihui(State Key Laboratory of Powder Metallurgy,Central South University,Changsha,410083,China;AECC South Industry Co.,Ltd,Zhuzhou 412002,China;Zunyi Titanium Co.,Ltd,Zunyi,563004,China)

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083 [2]中国航发南方工业有限公司,株洲412002 [3]遵义钛业股份有限公司,遵义563004

出　　处：《粉末冶金材料科学与工程》2020年第3期245-250,共6页Materials Science and Engineering of Powder Metallurgy

基　　金：国家重点研发计划资助项目(2017YFB0305401)。

摘　　要：以氯化钠−氯化钾作为熔盐,采用熔盐电解法对海绵钛阴极片进行提纯,通过对电解过程形核率的理论推导,分析电解温度及不同熔盐成分比例对高纯钛结晶形貌的影响,研究熔盐电解过程中的结晶机理。结果表明,随电解温度升高,结晶钛颗粒尺寸逐渐增大,结晶颗粒由长条状或椭圆状逐渐转变为树枝状。熔盐成分中KCl含量增大会导致熔盐电阻增加,电流效率下降,致使结晶钛颗粒尺寸减小,结晶钛疏松,夹盐率高。通过对结晶钛颗粒进行微观表征,发现熔盐电解过程中,钛晶体台阶状生长,为二维形核方式。电解钛粉不是一个单晶整体,而是含有许多纳米晶及亚晶的多晶体,晶粒尺寸为100~500 nm。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.

关 键 词：高纯钛 熔盐电解 结晶 电解质 形核率 

分 类 号：TF823[冶金工程—有色金属冶金]