Abstract The electrodeposition mechanism, microstructures and corrosion resistances of Ni–Cu alloy coatings on Cu substrate were investigated in a choline chloride–urea (1:2 molar ratio) eutectic-based ionic liquid (1:2 ChCl–urea IL) containing nickel and copper chlorides. Cyclic voltammetry showed that the onset reduction potentials for Cu (∼−0.32 V) and for Ni (∼−0.47 V) were close to each other, indicating that Ni–Cu co-deposition could be easily achieved in the absence of complexing agent which was indispensable in aqueous plating electrolyte. Chronoamperometric investigations revealed that Ni–Cu deposits followed the three-dimensional instantaneous nucleation/growth mechanism, thus producing a solid solution. The compositions, microstructures and corrosion resistances of Ni–Cu alloy coatings were significantly dependent on the deposition current densities. Ni–Cu alloy coatings were α-Ni(Cu) solid solutions, and the coating containing ∼17.6 at.% Cu exhibited the best corrosion resistance because of its dense and crack-free structure.

中文翻译：

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共晶基离子液体Ni-Cu合金涂层的电沉积机理和表征

摘要 在含镍和氯化胆碱-尿素（1:2 摩尔比）共晶离子液体（1:2 ChCl-尿素 IL）中研究了 Cu 基体上 Ni-Cu 合金涂层的电沉积机理、微观结构和耐腐蚀性能。氯化铜。循环伏安法表明，Cu (~-0.32 V) 和 Ni (~-0.47 V) 的起始还原电位彼此接近，表明在没有络合剂的情况下可以很容易地实现 Ni-Cu 共沉积。在水性电镀电解液中是必不可少的。计时电流分析表明，Ni-Cu 沉积物遵循三维瞬时成核/生长机制，从而产生固溶体。组成，Ni-Cu 合金涂层的微观结构和耐腐蚀性显着取决于沉积电流密度。Ni-Cu 合金涂层是 α-Ni(Cu) 固溶体，含有 17.6 at.% Cu 的涂层由于其致密且无裂纹的结构而表现出最好的耐腐蚀性能。