(1. 哈尔滨工业大学 化工学院，哈尔滨 150001；
2. 杭州东方表面技术有限公司，杭州 311122)
摘 要: 为解决电镀铬工艺严重污染环境的问题，制备低污染且具有良好外观的Ni-Co-B合金代硬铬镀层。采用单因素实验分别讨论电镀液组成及工艺条件对镀层硬度、外观、沉积速度及阴极电流效率等的影响，确定较优的镀液组成及工艺条件，考察优化条件下所得镀层经不同温度热处理后的镀层硬度，分析镀液的极化情况和200 ℃热处理1 h前后镀层的表面形貌、晶体结构及耐蚀性。结果表明：优化条件下得到的合金镀层为纳米晶结构，宏观上均匀光亮，微观上平整、无孔隙，经200 ℃热处理1 h后晶体颗粒进行重结晶，晶粒尺寸略有增大，镀层表面更加致密，硬度达10.875 GPa，高于硬铬镀层的，且耐蚀性与硬铬镀层的相当。该电镀工艺有望取代电镀硬铬工艺而获得广泛应用。
关键字: Ni-Co-B合金；纳米晶；电镀；代铬镀层；显微硬度
（1. School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, China;
2. Hangzhou Oriental Metal Finishing Technology Co., Ltd., Hangzhou 311122, China）
Abstract:To solve the problem of serious environmental pollution from electroplating chromium process, electroplating Ni-Co-B alloy coatings, which are environment-friendly and with good appearance, were prepared to substitute the hard chromium coating. The effects of electrolyte solution composition and process conditions on the microhardness, appearance, deposition rate of the coatings and current efficiency of the cathode were discussed by single factor experiments. Relatively better compositions of the electrolyte and process conditions were gained. The effects of different heat treatment temperatures on the microhardness of the coatings prepared under the optimized condition were measured. The polarization of electrolyte was analyzed. The surface morphology, microstructure and corrosion resistance of the coatings before and after heat treatment at 200 ℃ for 1 h were characterized. The results show that alloy coatings prepared under the optimized condition are nanocrystalline structure, bright and uniform in macrography, smooth and seamless in micrography. After heat treatment, the grain sizes of coatings slightly increase because of recrystallization, the surfaces b, ecome more compact, and the microhardness can be up to 10.875 GPa, which is higher than that of hard chromium coating. Also, the corrosion resistance of alloy coatings after heat treatment is roughly equivalent to that of hard chromium coating. So, this electroplating process is expected to replace the hard chromium plating technology and be widely applied.
Key words: Ni-Co-B alloy; nanocrystalline; electroplating; substituting chromium coating; microhardness
