Ni-P-CNTs化学镀层在酸性溶液中的电化学腐蚀行为

Electrochemical Corrosion Behavior of the Electroless Ni-P-CNTs Composite Coating in Acidic Solution

为了更深地认识CNTs对Ni-P镀层电化学腐蚀性能的影响,采用复合化学镀技术,通过向优化的化学镀溶液中加入碳纳米管的方法在45#钢基材上制备了Ni-P-CNTs复合镀层,并用相同工艺在45#钢基材上直接化学镀Ni-P镀层作为对比。采用SEM/EDAX,XRD和TEM综合分析了复合镀层的形貌和结构,分析表明:所得镀层以非晶结构为主,碳纳米管均匀分布在镀层中。采用动电位极化及交流阻抗技术对比研究了Ni-P-CNTs复合镀层及纯Ni-P镀层在0.5mol/L NaCl+0.05mol/L H2SO4酸性溶液中的电化学腐蚀行为,腐蚀实验结果表明:在该介质溶液中,与不含碳纳米管的Ni-P镀层相比,Ni-P-CNTs复合镀层的自腐蚀电位和自腐蚀电流密度较低,耐均匀腐蚀性能得到明显改善;此外,碳纳米管的加入还明显提高了Ni-P镀层在该介质溶液中的耐点蚀性能。

Ni-P-carbon nanotubes （CNTs） composite coatings as well as Ni-P coatings on 45^# steel were pre- pared by electroless plating in order to investigate the effect of CNTs on the corrosion of the electroless Ni-P coating. The characteristics and microstrucrure of the coatings were assessed by SEM/EDAX, XRD and TEM. The results indicate the co-deposited CNTs are homogeneously dispersed in the mainly amorphous Ni-P alloys. The electrochemical corrosion behavior of the electroless Ni-P and Ni-P-CNTs composite coating in solutions of 0.5mol/L NaCl ＋ 0.05mol/L H2SO4 was investigated by using potentiodynamic polarization and capacitance measurement. The results show that the codeposited CNTs not only decrease the corrosion potential （Ecorr ） and corrosion current（ icorr） , but also increase the susceptibility to pitting corrosion of Ni-P coating.