铝黄铜基体电沉积Ni-P合金工艺

Technology for Electrodeposition of Ni-P Alloy Coating on Al-Brass Substrate

为了提高铝黄铜的耐蚀性能,采用次亚磷酸盐体系电镀Ni-P合金,从镀层沉积速度和外观角度,研究了镀液组成、pH值、电流密度、温度对镀层的影响,得出了最佳的工艺条件:40～60g/L硫酸镍,8～10g/L氯化镍,8～12g/L次亚磷酸钠,10～14g/L柠檬酸,25～35g/L硼酸,pH值2.5～3.0,电流密度45～55mA/cm2,温度58～70℃。采用本工艺得到的镀层均匀、光亮,耐蚀性优于铝黄铜。

Ni-P alloy coating was prepared on the surface of Al-brass substrate via electroplating in hypophosphite bath. The effects of bath composition and pH value,current density and temperature on the deposition rate and appearance of the Ni-P alloy coating were studied,and the optimized bath composition and plating parameters were determined. Results indicate that the optimized plating bath is composed of 40~60 g/L NiSO4,8~10 g/L NiCl2,8~12 g/L NaH2PO2·H2O,10~14 g/L C6H8O7,25~35 g/L H3BO3,while the optimized plating parameters are determined to be pH value of 2.5~3.0,current density of 45~55 mA/cm2 and temperature of 58~70 ℃. The coating obtained at the optimized technology was uniform and bright,and had better corrosion resistance than Al-bass.