摘要
利用循环伏安和计时安培研究Sn-Cu合金体系在玻碳电极上的电沉积行为,通过阴极极化曲线、SEM观察及EDS分析讨论柠檬酸和硫脲对Sn-Cu共沉积的影响。结果表明,Sn-Cu共沉积过程为扩散控制的不可逆过程;在沉积电位-600～-750mV的范围内Sn-Cu共沉积初期结晶行为满足三维Scharifker-Hills瞬时成核模型,随着过电位的增大,形核活性点增多,形核弛豫时间缩短;当沉积过电位大于-700mV时,Sn2+的扩散系数约为6.435×10-6cm2/s;柠檬酸和硫脲的加入细化了镀层晶粒,使镀层表面更加平整和致密。此外,硫脲的加入降低了镀层中铜的含量,使合金镀层中铜的含量维持在0.5%～2.0%(质量分数)。
The electrodeposition of Sn-Cu alloy system on the glass carbon electrode was investigated by cyclic voltammetry（CV） and chronoamperometry（CA）.The effect of citric acid and thiourea additives on Sn-Cu alloy codeposition was discussed by cathodic polarization curve,SEM observation and EDS analysis.The results indicate that the electrodeposition process of Sn-Cu is an irreversible process controlled by diffusion,and the codeposition of Sn-Cu alloy system in the initial stage follows Scharifker-Hills（SH） instantaneous nucleation/growth mechanism in the potential range of-600--750 mV.With increasing the overpotential,the activity-point for nucleation increases,and the nucleation relaxation time reduces.When the deposition overpotential is higher than-700 mV,the diffusion coefficient of Sn2 ＋ is 6.435×10-6cm2/s.The addition of citric acid and thiourea refines grains in coating and the surface of coating becomes more even and compact.The presence of thiourea reduces clearly the copper content in coating and makes the copper content remain in the range of 0.5%-2.0%（mass fraction）.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2010年第5期1006-1012,共7页
The Chinese Journal of Nonferrous Metals
基金
民口配套资助项目(MKPT-98-106)
关键词
Sn-Cu合金
形核
循环伏安
电沉积
Sn-Cu alloy
nucleation
cyclic voltammetry
electrodeposition
