采用两级跳间歇镀电源的无氰碱铜研究

Study on cyanide-free alkaline copper plating by using a two-stage switching power supply for intermittent electroplating

回顾了多年来对无氰碱铜研究的经验教训。提出了一种采用冲击镀转间隙镀两级跳自动电源的无氰碱铜工艺。该工艺的临界活化电流密度很小,并能保证钢铁件上在较宽的电流密度范围内直接预镀铜而取得良好结合力。采用赫尔槽试验,讨论了主盐类型及阴、阳离子杂质对镀层外观的影响。结果表明,采用碱式碳酸铜作为主盐的效果最好。该工艺抵抗杂质的能力较强。加入适量硝酸钾能降低液温并提高允许电流密度,有利于无氰加厚镀铜及复杂管件的装饰镀。

The experiences and lessons from the research of cyanide-free alkaline Cu plating were retrospected. A cyanide-free alkaline Cu plating process using a strike-to- intermittence two-stage automatic switching power supply was developed. The process features low critical current density for activation and guarantees good adhesion of Cu strike directly plated on iron and steel workpiece to the substrate. The effects of the type of main salt and anionic/cationic impurities on the appearance of deposit were discussed by Hull-cell tests. The results showed that the use of basic copper carbonate as main salt has optimal effectiveness. The process has relatively strong resistance to impurities. A proper addition of KNO3 decreases the bath temperature and increases the allowable current density, facilitating the cyanide-free thickening of Cu coating and decorative plating of complicated pipe pieces.