电沉积Ni-Sn-Mn非晶镀层镀液组分优化及耐蚀性

Plating Bath Composition Optimization and Corrosion Resistance of Ni-Sn-Mn Amorphous Coating Prepared by Electrodeposition

为了提高低碳钢在海洋环境中的耐蚀性,采用脉冲电沉积技术在Q235钢表面制备Ni-Sn-Mn合金镀层,通过正交试验方法对镀液组分进行优化。利用扫描电镜(SEM)及附带的能谱仪(EDS)、X射线衍射仪(XRD)、Tafel曲线和电化学阻抗谱(EIS)等方法对镀层表面形貌、元素含量、相结构及耐蚀性进行分析。结果表明:脉冲电沉积Ni-SnMn镀层最优镀液组分为:10 g/L SnCl_2·2H_2O、55 g/L NiSO_4·6H_2O、50 g/L MnSO_4·H_2O和160 g/L Na_3C_6H_5O_7·2H_2O。最优镀液组分条件下制备的镀层为非晶态结构,镀层表面胞状颗粒均匀致密。镀层中Ni、Sn、Mn的质量分数分别为68.59%、21.57%、9.84%。与Ni-Sn镀层相比,Ni-Sn-Mn镀层在3.5%NaCl溶液中的自腐蚀电位(-0.346 V)更正,自腐蚀电流密度(2.816×10^(-8) A/cm^2)更低,电荷转移电阻(12 580Ω·cm^2)更大,耐蚀性更好。

To improve the corrosion resistance of mild steel in marine environment, Ni-Sn-Mn alloy coatings were prepared on the surface of Q235 steel by pulse electrodeposition. Plating bath composition was optimized by orthogonal experiment method. Surface morphology, element content, phase structure, and corrosion resistance of the Ni-Sn-Mn coatings were evaluated by scanning electron microscopy （SEM） with energy dispersive spectrometer （EDS）, X-ray diffraction （XRD）, Tafel curve and electrochemical impedance spectroscopy （EIS）. The results show that the optimized plating solution consists of 10 g/L nCl2·2H2O, 55 g/L iSO4·6H2O, 50 g/L MnSO4·HeO and 160 g/L Na3C6H5O7·2H2O Ni-Sn-Mn coating deposited under optimized plating bath composition has an amorphous structure. Uniform and fine cellular particles are distributed densely on the surface of the coating. The mass fractions ofNi, Sn and Mn in the coating are 68.59%, 21.57% and 9.84%, respectively. Compared with the Ni-Sn coating, the Ni-Sn-Mn coating exhibits better corrosion resistance in 3.5% NaC1 solution shown by a more positive corrosion potential （-0.346 V）, a lower corrosion current density of 2.816×10^-8 A/cm^2, and a bigger charge transfer resistance of 12 580 Ω·cm^2.