硫酸盐三价铬滚镀黑铬工艺研究

Study on trivalent black chromium barrel plating process in sulfate electrolyte

开发了Trich-7377硫酸盐三价铬滚镀黑铬的新工艺。根据赫尔槽试验结果,分析了影响镀液覆盖能力、沉积速率和稳定性的因素。在综合考虑覆盖能力、沉积速率、稳定性和镀层性能的前提下,选择了较适宜的滚筒转速、装载量、槽电压、镀液温度、pH等工艺参数。介绍了镀液的具体组成和维护方法。该工艺镀液稳定,操作简单,便于维护。所得镀层光滑,呈枪黑色,中性盐雾试验48 h不变色,人造汗液测试、恒定湿热试验和结合力测试均合格。

A novel Trich-7377 process of trivalent black chromium barrel plating in sulfate electrolyte was developed. The factors affecting covering power, deposition rate, and stability of the plating bath were analyzed according to the results of Hull cell test. Suitable process parameters including barrel rotation rate, loading capacity, tank voltage, bath temperature, and pH were selected on the basis of comprehensive considerations of covering power, deposition rate, bath stability, and coating performance. The detailed composition and maintenance methods of plating bath were introduced. The plating bath has advantages of high stability, simple operation, and easy maintenance. The chromium coating obtained is smooth and gun black, does not tarnish after neutral salt spray test for 48 h, and can pass the artificial sweat test, constant damp-heat test, and adhesion strength test.