脉冲电沉积时间对Sn-Zn-Mn合金镀层的影响

Effect of pulse electrodeposition time on Sn-Zn-Mn alloy coating

为了提高低碳钢在海洋环境下的耐蚀性,采用脉冲电沉积技术在Q235钢表面成功沉积出Sn-Zn-Mn镀层。利用辉光放电光谱仪（GDS）、扫描电镜（SEM）、塔菲尔（Tafel）极化曲线和电化学阻抗谱（EIS）考察了施镀时间对元素成分、镀速、表面形貌、阴极电流效率和耐蚀性的影响。结果表明：随施镀时间的增加,w（Sn）和w（Zn）减小,w（Mn）增大;镀速和沉积电流效率呈先增大后减小的趋势;镀层胞状颗粒尺寸增大;耐蚀性先提高后降低。施镀时间为30 min时,所得Sn-Zn-Mn镀层表面平整光滑、组织均匀致密,在3.5%Na Cl腐蚀液中具有最正的E（corr）值（-0.394 V）、最低的I（corr）值（1.585×10（-8）A·cm（-2））和最大的R（ct）值（8653Ω·cm2）,耐蚀性最好。

In order to improve the corrosion resistance of mild steel in marine environment,Sn-Zn-Mn alloy coating was deposited on the surface of Q235 steel by means of pulse electrodeposition.The effect of deposition time on coating element content,deposition rate,surface morphology,cathode current efficiency and corrosion resistance were investigated by using glow discharge spectroscopy（GDS）,scanning electron microscopy（SEM）,Tafel polarization curve and electrochemical impedance spectroscopy（EIS）,respectively.The results show that with the increasing of deposition time,the mass fraction of Sn and Zn decreases,while the increase of Mn content.The deposition rate of coating and cathode current efficiency of electrodeposition first increase and then decrease.The grain size increases gradually.Corrosion resistance of the coating first increases and then decreases.The surface of Sn-Zn-Mn alloy coating prepared with the deposition time of 30 min is glossy and smooth,and the microstructure is uniform and compact,and in 3.5%Na Cl solution has the most positive corrosion potential（-0.394 V）,the smallest corrosion current density（1.585×10（-8）A·cm（-2））,and the biggest charge transfer resistance（8653Ω·cm2）,which exhibits the best corrosion resistance.