无氰碱性镀铜研究

【作者】 段光亮；

【导师】 李永富；

【作者基本信息】 南京理工大学 ， 应用化学， 2008， 硕士

【摘要】 为顺应国家淘汰氰化物电镀的行业政策，保护环境，本文以无氰碱性镀铜为研究对象，试图开发出成本低、具实用性的环境友好型无氰镀铜液。考虑到焦磷酸盐、HEDP等含磷络合剂废水处理困难，含氨基络合剂镀铜液在电镀过程中易产生Cu⁺等诸多因素，本文选择碱性条件下对Cu²⁺络合能力较强的柠檬酸为主络合剂作为研究对象，进行了镀液开发和试验测试。研究表明，仅由柠檬酸、铜离子、碱组成的碱性配方普遍存在彩色镀铜层。加入硼酸、葡萄糖酸钠、氨基磺酸等均可消除彩色镀层，使赫尔槽电镀试片呈有序规律地变化。加入氨基磺酸和葡萄糖酸钠效果显著，消除彩色镀层的效率明显优于硼酸系添加物。但过量加入葡萄糖酸钠对镀层有其它负面影响。对彩色镀铜层的系统研究很少见有文献报道，通过文献检索发现在镀铜液配方中加入氨基磺酸组分以及该组分在镀液中所起作用的报道也很少。FL作为辅助络合剂可较明显地改善镀层质量。辅助络合剂改变了碱性条件下柠檬酸与铜之间的双核多元络合物Cu₂（OH）₂(H_-1Cit)₂^6-等结构，改变了Cu²⁺电沉积的电化学过程。自行开发的复合添加剂TJ可明显地增加阴极极化，使铜络离子在阴极的沉积变得困难，沉积速度降低，结晶细致、结合力好。复合添加剂TJ的主要成分未发现在电镀行业中使用的报道。试验结果表明，大豆蛋白胨等高分子化合物可在阴极表面吸附，提高镀层、特别是电流密度高区镀层的质量。线性伏安曲线测定表明铜离子的阴极还原过程分两步进行。其电极主要过程受电化学控制，同时也受扩散控制。通过对镀液中各组分优化试验和工艺条件试验，确定了以柠檬酸为主络合剂的较好配方为：铜离子20g/L～30g/L（以碱式碳酸铜形式加入），柠檬酸160g/L～200g/L，辅助络合剂FL 12g/L～24g/L，氨基磺酸2g/L～6g/L，大豆蛋白胨0．1g/L～0．2g/L，复合添加剂TJ 2g/L～3g/L，pH约9．5，镀液温度30℃～40℃，电流密度范围0．1A／dm²～1．4A／dm²。更多还原

【Abstract】 As to conform the policy of replacing cyanide electroplating, and to protect environment, this paper chooses non-cyanide copper electroplatig as our research object. We try to develop a low-cost, practical and environment friendly non-cyanide copper electrolyte. Considering the phosphorous wastewater such as wastewater containing pyophosphate and HEDP is hard to treat, and considering the Cu⁺ is easy to form in the copper electrolyte containing -NH₂ complexing agent, this paper chooses citrate as the major complex agent, which can complexes well with cupric in the alkaline environment. With citrate as our research object, and we do the job of electrolyte developing and some testing.With our research, from an alkaline bath which is only containing citrate, cupric and alkali, we ofen get a multicolored copper coating. Adding boric acid, sodium gluconate or aminosulfonic acid can eliminate the multicolored copper coating, and make the coating on the Hull-trough testing pattern change regularly. The effect of eliminating multicolored coating through adding aminosulfonic acid or sodium gluconate is very obvious, and the efficiency is better than adding boric acid series. But adding excess sodium gluconate may give a bad effect to the coating. There is very few literatue systematically researchs on multicolored copper coating. Through literatue search, we find very few reports of adding aminosulfonic acid in copper eletroplating bath, and we did not find any report of the effect of amidosulphonic acid in copper eletroplating bath.The auxiliary complex agent FL can improve the quality of copper coating. The auxiliary complex agent changes the structure of the dimer Cu₂（OH）₂(H_-1Cit)₂^6-, which is dominant in our alkaline electrolyte. And the auxiliary complex agent also changes the electrochemical process of copper electrodeposition. Adding the mulripe electroplating addtives TJ can obvious increase cathode polarization, and make the copper electrodiposition slower. The adding of TJ make the coating brighter, and improve the adhesion with the substrate too. The main component of TJ has not found being used as electroplating addtive in the electroplating industry. Through our test, we found soya peptone can adsorb on the surface of cathode, and improve the quality of the coating, especially in the high current density zone. From the voltammetric curves, we find the electrode process is under electrochemistry control and diffusion control.Through the Hull-trough test, we determine a good formula for copper electroplating which based on citrate as the major complex agent. The formula and the elctroplating process conditions is copper（add to electrolyte by the cupric salt:Cu₂（OH）₂CO₃） 20g/L～30g/L, citric acid monohydrate 160g/L～200g/L, auxiliary complex agent FL 12g/L～24g/L, aminosulfonic acid 2g/L～6g/L, soya peptone 0.1g/L～0.2g/L, the mulripe electroplating addtives TJ 2g/L～3g/L, pH9.5, 30℃～40℃, current density of 0.1A/dm²～1.4A/dm².更多还原