Ni-Co-C代硬铬镀层的制备及性能研究(Ⅰ):镀液组成及工艺优化

Studies on the Preparation and Properties of Ni-Co-C Coating Substituting for Hard Chromium Coating(Ⅰ): Optimization of the Bath Composition and Electroplating Process

为提高Ni-Co合金镀层的致密性、硬度、耐磨性和耐蚀性等各方面性能,采用电沉积方法在镀层中引入原子态的碳。对Ni-Co-C代铬镀液中可能的碳源进行了筛选,并利用单因素试验对镀液中各组分的含量及工艺条件进行了优化,最终确定了草酸铵-柠檬酸铵体系为Ni-Co-C代铬镀液体系。得到的镀层外观与暗镍类似,结晶较细,平整性和均匀性稍差。优化的Ni-Co-C基础镀液稳定性好,长期放置不结晶、不沉淀;阴极电流效率稳定在45%~48%。

For improving the compactness,hardness,wear resistance and corrosion resistance of Ni-Co alloy coating,atomic carbon was added into the Ni-Co coating by electrodeposition method. The possible carbon source in the Ni-Co-C chromium plating bath was screened,the content of each component in the plating bath and processing condition were optimized by using single factor experiments,finally,the ammonium oxalate-ammonium citrate system was determined as the substitute for the Ni-Co-C plating bath system. Appearance of the obtained coating was similar to that of dark nickel,the crystallization was fine,and the smoothness and uniformity were a little poor. Stability of the optimized Ni-Co-C basic bath was good,no crystallization and precipitation after long-term storge,the cathodic current efficiency was stable at 45% ~ 48%.