乙酰胺-尿素-NaBr熔体中Gd-Ni合金的电化学制备

Electrochemical Preparation of Gd-Ni Alloy Film in Acetamide-urea-NaBr Melt

熔盐电解法制取稀土合金功能材料具有低成本等优点.本文选取353 K的乙酰胺-尿素-NaB r熔体,应用循环伏安法研究镍于该熔体(含0.063 mol.L-3N iC l2)、Pt、Cu电极上的还原.实验表明,N i(Ⅱ)+2 eN i(0)是一步完全不可逆反应,测得在Pt上N i(Ⅱ)的传递系数α=0.28,扩散系数D0=4.63×10-5cm2.s-1,Cu上α=0.22,D0=6.05×10-7cm2.s-1.以Cu作基体,Gd(Ⅲ)于该熔体不能单独还原为Gd(0),但可以被N i(Ⅱ)诱导共沉积.由恒电位法电解得到的Gd-N i合金,Gd(0)的含量随电解电位、Gd(Ⅲ)/N i(Ⅱ)摩尔比及电解时间的变化而变化.控制电解电位为-0.75 V,Gd(Ⅲ)/N i(Ⅱ)摩尔比为1∶1,电解20 m in.所得合金膜是非晶态的.

Cyclic voltammetry was used to study the electroreduction of Ni^2＋ to Ni on Pt and Cu electrode in acetamide-urea-NaBr melt at 353K. It is irreversible in one step . At Pt and Cu eletrode the diffusion coefficient and electron transfer coefficient of Ni^2＋ in 0. 063mol/dm^3 NiCl2- acetamide-urea-NaBr melt were determined. The transfer coefficient α =0.28 and diffusion coefficient Do =4.63 × 10^ -5 cm^2 ·s^-1 of the Pt eletrode and transfer coefficient α =0.22 and diffusion coefficient Do = 6.05 × 10^-7 cm^2 ·s^-1 of the Cu eletrode were measured. It was put emphasis on that Gd^3 ＋ is not reduced to Gd alone in copper matrix, but can be inductively codeposited with Ni^2＋. The amorphous Gd-Ni alloy films were obtained by potentiostatic electrolysis . The content of Gd in the Gd-Ni deposits changes with the cathode potential , molar ratio of Gd^3 ＋/Ni^2＋ and the electrolysis time . Under the condition of electrolyte potential -0.75 V and molar ratio of Gd （ Ⅲ）/Ni （ Ⅱ ） 1 ： 1, the alloy film obtained after electrolysis 20 min is amorphous state.