氯化铵对氯化胆碱-尿素低共熔溶剂电沉积锌-镍合金的影响

Effect of ammonium chloride on electrodeposition of zinc-nickel alloy from choline chloride−urea deep eutectic solvent

采用氯化胆碱-尿素低共熔溶剂电沉积Zn–Ni合金。通过循环伏安法和计时电流法研究了Zn–Ni合金镀液中添加不同浓度NH_(4)Cl时的电沉积行为。采用扫描电镜、能谱仪、X射线衍射仪及塔菲尔曲线测量、电化学阻抗谱等电化学手段研究了NH_(4)Cl浓度对Zn–Ni合金镀层表面形貌、成分和耐蚀性的影响。结果表明,Zn–Ni合金电沉积过程的氧化还原反应均为不可逆电极反应。随NH_(4)Cl浓度的增大,Zn–Ni合金的还原峰正移,镀层的晶粒尺寸和Zn质量分数减小,但晶相结构变化不大,耐蚀性先改善后变差。NH_(4)Cl浓度为0.2 mol/L时所得Zn–Ni合金镀层具有最佳的表面形貌和耐蚀性。

Electrodeposition of Zn–Ni alloy was conducted in a choline chloride−urea deep eutectic solvent.The effect of NH_(4)Cl concentration in the deep eutectic solvent on the electrodeposition behavior of Zn–Ni alloy was studied by cyclic voltammetry and chronoamperometry,and that on the surface morphology,composition,and corrosion resistance of electrodeposited Zn–Ni alloy coating was studied by scanning electron microscopy,energy-dispersive spectroscopy,X-ray diffraction,Tafel polarization curve measurement,and electrochemical impedance spectroscopy.The results indicated that the oxidation and reduction occurring during the electrodeposition of Zn–Ni alloy were irreversible electrode reactions.The increase of NH_(4)Cl concentration made the reduction peak of Zn–Ni alloy in cyclic voltammogram shifted positively,resulting in a decrease in grain size and Zn content of Zn–Ni alloy coating,but slightly changed the crystal structure of Zn–Ni alloy coating.The corrosion resistance of Zn–Ni alloy coating was improved firstly and then decreased with the increasing of NH_(4)Cl concentration.The Zn–Ni alloy coating electrodeposited with 0.2 mol/L NH_(4)Cl in the deep eutectic solvent had the best surface morphology and corrosion resistance.