Ni-P/Ni-W-P双层镀层宏观和微观耐蚀性研究

Research on Macro/micro Corrosion Resistance of Ni-P/Ni-W-P Coatings

采用恒电位极化法结合特殊点微观扫描的方法研究了Ni-P/Ni-W-P双层化学镀层的宏观与微观耐蚀性能。研究表明,Ni-P/Ni-W-P双层镀层的阳极极化曲线具有相当稳定的钝化区,较之相同配方的Ni-W-P单层镀层具有更小的维钝电流密度。两种镀层的腐蚀都是由胞状物开始,并逐渐向边界扩展。

By combining anode polarizing curves and corrosion shape under corresponding electric potential, the corrosion properties of Ni-P/Ni-W-P coatings were studied. The results show that the polarizing curves of Ni-P/Ni-W-P double coatings possess stable passivation area. The double coatings take on less density of maintaining passivity current compared with the same composition of Ni-W-P single coating. The corrosion of both double and single coating spreads from cell like to boundary.