摘要
为了进一步提高Ni-P镀层的耐蚀性能,在Ni-P化学镀液中加入硫酸铜制备了Ni-Cu-P三元合金化学镀层,测试了镀层的沉积速度,采用扫描电镜(SEM)观察了镀层的表面形貌,测试了镀层在5.0%H2SO4,5.0%NaOH及3.5%NaCl溶液中的动电位极化曲线,并与Ni-P化学镀层进行了比较。结果表明:Ni-Cu-P镀层表面的胞状物比Ni-P镀层的更加细小,镀层致密性更好;Ni-Cu-P镀层在3种介质中均表现出更好的耐均匀腐蚀性和抗点蚀性能,主要是因为Ni-Cu-P镀层的非晶态结构减少了镀层缺陷数量,从而减少了腐蚀发生的敏感位置和腐蚀微电池的数量,同时更加细小的晶粒也使Ni-Cu-P镀层比Ni-P镀层更容易钝化和维持钝态,另外Ni-Cu-P镀层更为致密也减少了腐蚀介质渗入基体的通道。
CuSO 4 was added into electroless Ni-P bath to prepare Ni-Cu-P ternary alloy coating so as to improve the corrosion resistance of Ni-P electroless coating.The surface morphology of the coating was observed using a scanning electron microscope,and its corrosion resistance in 5.0 % H 2 SO 4,5.0 % NaOH and 3.5 % NaCl solutions was evaluated by measuring the potentiodynamic polarization curves.It was found that Ni-Cu-P coating had finer nodular structure and better compactness than Ni-P coating.In the meantime,Ni-Cu-P coating showed better resistance to general corrosion and pitting in the three kinds of corrosive solutions than Ni-P coating.The reason lay in that the ternary coating contained amorphous phase,which reduced the amount of defects thereby reducing the amounts of corrosion positions and corrosion microcells.Moreover,the Ni-Cu-P coating composed of finer grains with better compactness was more liable to be passivated and remain passivating status,thereby more effectively preventing the corrosive mediums from penetrating into the substrate.
出处
《材料保护》
CAS
CSCD
北大核心
2012年第3期8-10,3,共3页
Materials Protection
