Thermodynamics analysis of Ni^(2+)-C_2H_8N_2- C_2O_4^(2-)-H_2O system and preparation of Ni microfiber  

Ni^(2+)-C_2H_8N_2-C_2O_4^(2-)-H_2O体系的热力学分析及Ni微米纤维的制备(英文)

作　　者：姚永林[1] 张传福[1] 湛菁[1] 丁风华[1] 邬建辉[1] 

机构地区：[1]中南大学冶金与环境学院,长沙410083

出　　处：《Transactions of Nonferrous Metals Society of China》2013年第11期3456-3461,共6页中国有色金属学报（英文版）

基　　金：Project(CX2012B046)supported by Hunan Provincial Innovation Foundation for Postgraduate,China;Project(20090162120080)supported by the Doctorate Fund of Education Minister of China

摘　　要：According to the principles of simultaneous equilibrium and mass equilibrium, the thermodynamics model of the precipitation-coordination equilibrium of Ni2＋-C2H8N2- 2-2 4C O -H2O system was established, and calculation for the relationships between concentration of each substance in solution and parameters was carried out, including pH value, concentrations of ethylenediamine and oxalate by MATLAB program. The results show that Ni exists as Ni2＋and [Ni（C2O4）n]2-2n mainly at pH〈1 and pH=1-6, respectively. When pH〉6, the complex between Ni2＋and ethylenediamine is predominant. The precursor of Ni microfiber was prepared by an oxalate precipitation process using ethylenediamine as a coordination agent, and the role of ethylenediamine in the growth of the precursor fiber was discussed. The Ni microfiber can be obtained by a thermal decomposition-reduction process of the precursor in N2 and H2 mixed atmosphere. The diameters and aspect ratios of the obtained Ni microfibers are 0.2-1 μm and 20-30, respectively.根据同时平衡和质量平衡原理,建立了Ni2+-C2H8N2-2?24C O-H2O体系的沉淀-配合平衡热力学模型,并对该模型进行计算来揭示该体系中各物种浓度随pH值、草酸及乙二胺浓度的变化规律。结果表明,当pH<1和pH=1-6时,溶液中的Ni分别主要以游离Ni2+及[Ni(C2O4)n]2-2n形式存在。当pH>6时,Ni2+与乙二胺的配合作用占优势。当用乙二胺作配位剂,采用草酸盐沉淀法制备了Ni微米纤维前驱体,并讨论了乙二胺在前驱体生长机制中的作用。将前驱体在N2和H2混合气氛中热分解还原,可得到直径0.2~1μm、长径比20~30的Ni微米纤维。

关 键 词：thermodynamics analysis Ni microfiber PRECURSOR thermal decomposition REDUCTION 

分 类 号：O611.4[理学—无机化学]