乙酰胺-尿素-NaBr熔体中Gd-Ni合金的电化学制备

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.

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

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) NiCl_(2)-acetamide-urea-NaBr melt were determined.The transfer coefficient α=0.28 and diffusion coefficient D_(0)=4.63×10~(-5) cm~(2·)s~(-1)of the Pt eletrode and transfer coefficient α=0.22 and diffusion coefficient D_(0)=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-0.75V and molar ratio of Gd(Ⅲ)/Ni(Ⅱ)1:1,the alloy film obtained after electrolysis 20 min is amorphous state.