Ni-Cr-P化学镀层的制备与电化学腐蚀行为

通过化学镀技术制备Ni-Cr-P三元合金镀层。利用称重法,SEM,EDS,XRD和电化学测试等方法,研究镀液中CrCl3,C3H6O3,C2H5NO2和K2C2O4浓度对Ni-Cr-P镀层的沉积速率、Cr含量及其在模拟燃料电池环境中电化学腐蚀行为的影响。结果表明,CrCl3浓度增加,沉积速率提高;随着C3H6O3,C2H5NO2和K2C2O4浓度的增加,沉积速率不断降低。Ni-Cr-P镀层的表面形貌呈胞状结构,镀层为非晶和微晶混合结构。Ni-Cr-P镀层的自腐蚀电位远高于Ni-P二元合金镀层的,向正移动约0.25 V;其电荷转移电阻增大,腐蚀电流密度降低了约两个数量级,Ni-Cr-P三元合金镀层的耐蚀性明显优于Ni-P二元合金镀层的。

Preparation and Electrochemical Corrosion Behavior of Electroless Plated Ni-Cr-P Alloy Coating

Ni-Cr-P alloy coatings on Q235 steel were prepared by electroless plating.The effect of CrCl3,C3H6O3,C2H5NO2 and K2C2O4 on the structure,composition and corrosion resistance of the prepared coatings was investigated by means of X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results show that with the increase of concentration of lactic acid,glycine,and potassium oxalate,the deposition rate was decreased continuously.In the contrast,the deposition rate was increased continuously with the increase of concentration of chromium chloride.The Ni-Cr-P coatings presented a surface morphology of cauliflower-like microstructures composed of a mixture of polycrystalline and amorphous.Notably,the anticorrosion performance of the Ni-Cr-P coatings were found to be much better than that of the Ni-P coatings.