鉴于电沉积Ni-Co-Zn三元合金中Zn²⁺与Ni²⁺、Co²⁺标准还原电势差异大，优先析出的Zn会吸附在电极表面并形成Zn(OH)₂沉淀膜，阻碍后续Ni²⁺和Co²⁺还原放电，不利于合金共沉积，本工作以抗坏血酸(H₂Asc)作为络合剂，通过调控镀液中Ni²⁺∶Co²⁺∶Zn²⁺摩尔浓度比，旨在实现Ni-Co-Zn三元共沉积。利用SEM、XRD等方法分析了离子摩尔浓度比和H₂Asc浓度对电沉积Ni-Co-Zn合金表面形貌和织构生长的影响。结果表明，当Ni²⁺∶Co²⁺∶Zn²⁺摩尔浓度比为4∶5∶1时，合金镀层中Ni含量高达12.2% (质量分数)，晶粒细化致密。当H₂Asc浓度为5 g/L时，织构生长呈类菜花球状，晶粒尺寸约为300 nm，具有最小的生长应力9.04 MPa。镀层中Zn含量随H₂Asc浓度增加而显著降低，而Ni + Co含量则逐渐上升，这主要归因于镀液中Zn²⁺与HAsc^-络合成了配位化合物[ZnHAsc]⁺并抑制了Zn的择优生长，留给Ni或Co更多的活性位点。合金中存在γ-Ni₅Zn₂₁、CoZn₁₃和Ni₃Zn₂₂等金属间化合物，说明适量H₂Asc的加入有助于实现合金共沉积。添加H₂Asc后试样的自腐蚀电位(E_corr)均大幅正移，降低了腐蚀驱动力；当H₂Asc添加量为5 g/L时，显示出最佳的耐腐蚀性能，其中E_corr正移了约200 mV，自腐蚀电流较未添加时降低了约75%。添加H₂Asc后试样的电化学阻抗谱(EIS)均由大半径的容抗弧和感抗弧组成，这是由于合金镀层中存在γ-Ni₅Zn₂₁相以及浸泡过程中形成的[Zn(OH)₄]^2-胶质微溶腐蚀产物，通过絮凝作用沉淀下来并包覆在活性Zn溶解后的活性表面，减少Cl^-向镀层内部扩散渗透的渠道，提高了其抗腐蚀性能。

Zinc-metal alloys with ferrous group metals such as Ni, Co, and Fe have been used for industrial applications due to their better corrosion performance compared to pure Zn. Among them, ternary Zn-Ni-Co alloys, which have superior corrosion resistance and magnetic features, have attracted extensive attention, and have been used as functional films in electro-mechanical system (EMS) devices and magnetic recording media. However, large differences in the reduction peak potential between Zn²⁺, Ni²⁺, and Co²⁺ restrict their codeposition because Zn-competitive adsorption hinders the discharge transfer of Ni²⁺ or Co²⁺. In view of the aforementioned statements, the effects of molar concentration ratios of Ni²⁺ : Co²⁺ : Zn²⁺ and the ascorbic acid (H₂Asc) concentrations in the bath on the surface features and textures of the Zn-Ni-Co alloys were assessed and characterized using FE-SEM, XRD, etc. Results showed that under the optimized condition of Ni²⁺ : Co²⁺ : Zn²⁺ = 4 : 5 : 1, the Ni content in the Ni-Co-Zn deposits reached 12.2%, which was instrumental in grain refinement. From the cyclic voltammetry curves, the potential of the reduction peak positively shifted from -1.47 V to -1.28 V, validating better codeposition with an appropriate H₂Asc concentration. SEM observations depicted a cauliflower-like texture with a crystal size of ~300 nm at a minimum growing stress of 9.04 MPa for the samples with 5 g/L H₂Asc concentration. From EDS analysis, with increasing H₂Asc concentration from 1 g/L to 5 g/L, the Ni + Co content in the Ni-Co-Zn deposits gradually increased but their Zn content decreased, which was attributed to the addition of H₂Asc in the form of [ZnHAsc]⁺ to offer more active sites for Ni or Co growth. Intermetallic compounds such as γ-Ni₅Zn₂₁, CoZn₁₃, and Ni₃Zn₂₂ were determined using XRD. The anticorrosive behavior was evaluated via potentiodynamic polarization (Tafel) tests in a 3.5%NaCl solution. The free corrosion potential (E_corr) positively shifted by ~200 mV for the samples with 5 g/L H₂Asc concentration and their corrosion current density (i_corr) has declined about 75% than those of the samples without H₂Asc. EIS results revealed a capacitive arc followed by a diffusion arc for the samples without H₂Asc, indicating pitting corrosion, and an inductive arc attached to a larger-radius capacitive arc for the samples with different H₂Asc concentrations, showing better corrosion resistance. This was due to the coexistence of the γ-Ni₅Zn₂₁ intermetallic phase and insoluble products [Zn(OH)₄]^2- that fully covered the Zn-dissolved active area to complete the corrosive channels via Cl^- diffusion, thus increasing the corrosion resistance of the Ni-Co-Zn alloys.