The pyrophosphate Cu-Sn alloy electroplating bath was comprised of cuprlc pyrophosphate and sodium stannate as the main salts, potassium pyrophosphate as the complexing agent and a self-made additive. The bath formula and technological conditions were optimized through Hull cell experiment. The bath properties including covering power, throwing power,cathodic current efficiency and deposition rate of were also tested. The results show that the covering power attains 98. 05% ,the throwing power in depth reaches 100 %, the average cathodic current efficiency is 86, 65% , and the average deposition rate is 59. 2μm/h. The cathodic polarizing ability of electrolyte has been improved and deposition potential of Cu-Sn alloy increased by the additives, obtaining a uruform, compact, bright and level Cu-Sn alloy coating.%以焦磷酸铜和锡酸钠为主盐,焦磷酸盐为配位剂,加入一种自制的铜-锡合金添加剂组成焦磷酸盐镀液,通过赫尔槽实验优选出最佳镀液配方和工艺条件,并对镀液的分散能力、深镀能力、阴极电流效率和沉积速率等性能进行测试.结果表明:镀液的分散能力为98.05%,深镀能力为100%,平均电流效率为86.65%,平均沉积速率为59.2 μm/h.加入添加剂后明显改善了镀液的极化性能,提高了铜离子及锡离子的析出电位,得到均匀致密、结晶细致、光亮整平的铜-锡合金镀层.
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