(中南大学 材料科学与工程学院，长沙 410083)
摘 要: 采用电镀法制备镀Ti金刚石-Ni-Co复合镀层，研究镀液中Co2+含量对镀层形貌和性能的影响，并通过电化学阻抗谱研究Ni-Co复合电沉积过程。结果表明：当镀液中未添加Co2+时，所制备的镀Ti金刚石-Ni复合镀层内凹痕较多；镀液中添加Co2+后，镀Ti金刚石-Ni-Co复合镀层内凹痕消失，晶粒均匀。随着镀液中Co2+含量的增加，所制备的镀Ti金刚石复合镀层的显微硬度先增加后减少。当镀液中Co2+含量为6%(摩尔分数)时，在-0.85 V电位下Ni-Co共结晶电化学阻抗谱的电荷转移电阻最大，制备的镀Ti金刚石-Ni-Co镀层内金刚石含量最高。此外，当镀液中Co2+含量增加至8%时，镀Ti金刚石-Ni-Co复合镀层内金刚石粉体的沉积量最少。
关键字: Ni-Co合金；金刚石；镀钛；复合电沉积；交流阻抗
（School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The Ti-coated-diamond-Ni-Co coating was prepared by electroplating process. Moreover, the effect of Co2+ content variation on the morphology and property of the Ti-coated diamond-Ni-Co coating was investigated. Meanwhile, the composite electrodeposition process was studied by electrochemical impedance spectroscopy (EIS). The results show that there are many dents on the Ti-coated diamond-Ni coating when Co2+ is not added in the plating bath. However, the dents disappear and the grain size becomes more uniform when Co2+ is added into the plating bath. Moreover, with the increase of Co2+ content in the plating bath, the microhardness of the composite coatings rises firstly and then declines. As Co2+ content in the plating bath is 6% (mole fraction), the charge transfer resistance of the Ni-Co codeposition evaluated from the EIS at -0.85 V reaches the maximum value, and the content of diamond in the composite coating is the highest. In addition, as Co2+ content in the plating bath increases to 8%, the content of diamond in the composite coatings is the least.
Key words: Ni-Co alloy; diamond; Ti plating; composite electrodeposition; alternating current impedance
