添加剂丙烯基硫脲对镍电沉积的影响研究

Effect of Allylthiourea on Nickel Electrodeposition from Solution Containing Ammonia and Chloride

采用循环伏安、线性扫描和恒电位阶跃电化学方法结合扫描电镜研究了不同浓度的丙烯基硫脲(ATU)对NH_3-NH_4Cl-H_2O体系镍在玻碳电极上的电沉积过程的影响.循环伏安测试、线性扫描以及恒电位暂态曲线一致表明ATU的加入对镍电沉积具有阻化作用,并且随着ATU浓度的增加其阻化作用增强.恒电位暂态曲线结果表明,镍的电结晶是按瞬时形核三维生长机理进行的,随外加电位负移,晶体向外生长速率增大,ATU的加入没有改变镍的形核方式,但形核数密度增大,并且减小晶体向外生长的速率.扫描电镜结果表明,ATU的加入可以细化晶粒,得到整平、致密的镍沉积层.

The effects of allylthiourea（ATU） concentration on the cathodic polarization behaviour,nucleation and surface morphology of nickel electrodeposited on the glassy carbon electrode from ammonia-ammonium chloride-water（NH3-NH4Cl-H2O）solutions were investigated by cyclic voltammogry,cathodic polarization and current transient methods.The results revealed that the addition of ATU inhibited nickel deposition,which was enhanced with an increase in ATU concentration from 5 to 50 mg·L-1.The initial deposition kinetics corresponded to a model including instantaneous nucleation and diffusion controlled growth.In the presence of ATU,the initial nucleation of nickel electrocrystallisation remained unchanged.However,the number density of nuclei increased and the crystal growth rate decreased.Furthermore,the addition of ATU apparently made the grains finer,leading to the formation of a more compact and uniform nickel deposit as compared with that without ATU.