(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用循环伏安(CV)和恒电位阶跃(CA)等电化学技术，研究金刚石粉体对Ni电结晶形核/生长的影响，并通过扫描电镜观察复合镀层的表面形貌。结果表明：在Ni-金刚石复合镀液中，金刚石粉体吸附在阴极表面，对阴极产生屏蔽作用，Ni2+的有效放电面积减小，阻碍电荷转移，使复合镀液在循环伏安曲线中的还原电流降低；金刚石粉体缩短了Ni电结晶的形核驰豫时间(tmax)，形核过电位正移，促进Ni电结晶形核；电镀时间越长，金刚石复合量越小，镀层表面越粗糙；Ni-金刚石复合镀液和纯Ni镀液的Ni电结晶形核可能为多晶沉积。
关键字: 金刚石；复合电镀；Ni；电结晶；形核；生长；多晶沉积
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effect of diamond powder on the nickel electrocrystallization nucleation/growth behavior was investigated by electrochemical techniques, such as cyclic voltammetry(CV) method and chronoamperometry method (CA), and the surface morphologies of composite coatings were observed by SEM. The results show that, in Ni-diamond electroplating solutions, diamond powder absorbed on the cathode surface decreases the effective area of Ni ion discharge and hinders the process of charge transfer because of the shielded cathode surface, which corresponds to much lower reduction current of CV curve; diamond powder shortens the nucleation relaxation time tmax of Ni electrocrystallization, the nucleation potential turns to positive direction, and Ni electrocrystallization is stimulated; the diamond powder content in Ni-diamond composite coatings decreases with the increase of electroplating time, which makes the surface of coatings coarsen; both Ni-diamond electroplating solution and pure Ni electroplating solution may follow the polycrystalline deposition mechanism.
Key words: diamond; composite electroplating; Ni; electrocrystallization; nucleation; growth; polycrystalline deposition
