配位剂和添加剂对钢铁基体化学置换镀铜的影响

Effects of complexing agents and additives on displacement plating of copper on steel substrate

研究了配位剂及添加剂对Q235钢上置换镀铜层的沉积速度、外观及耐腐蚀性能的影响。实验结果表明,三乙醇胺（TEA）和乙二胺四乙酸二钠（EDTA-2Na）双配位体系中铜的沉积速率适中,能够获得结晶细腻、结合力好的镀层,且镀层在质量分数为5%的盐酸溶液中的自腐蚀电位明显正移,腐蚀电流密度大大降低,耐蚀性显著提高。采用含吡啶、甲基蓝和硫脲的镀液,可以获得更加光亮的镀层;采用含乌洛托品、甲基蓝和吡啶的镀液,能获得最均匀、结合力最好、耐蚀性最强的镀层。较佳的钢铁件上置换镀铜配方及工艺条件为：硫酸铜20 g/L,EDTA-2Na 14 g/L,TEA 70 mL/L,NaCl 40 g/L,甲基蓝0.2 g/L,吡啶2.0 mL/L,硫脲0.10-0.25 mg/L,乌洛托品3 g/L,室温,pH 1.5,时间30 s。

The effects of complexing agents and additives on deposition rate,appearance and corrosion resistance of copper coating on Q235 steel by displacement plating were studied.The results indicated that the deposition rate of copper is moderate in a bath containing triethanolamine（TEA） and disodium ethylenediaminetetraacetate（EDTA-2Na）,and the coatings obtained feature fine grain,good adhesion,obvious positive shift of corrosion potential and significant decrease in corrosion current density in 5wt% HCl solution,showing enhanced corrosion resistance.Brighter coatings can be obtained from a bath containing pyridine,methyl blue and thiourea.Most uniform,best adhered and strongest anti-corrosive coatings can be obtained with urotropine,methyl blue and pyridine.The optimal bath formulation and process conditions for displacement plating of copper on steel substrates are as follows： copper sulfate 20 g/L,EDTA-2Na 14 g/L,TEA 70 mL/L,NaCl 40 g/L,methyl blue 0.2 g/L,pyridine 2.0 mL/L,thiourea 0.10-0.25 mg/L,urotropine 3 g/L,room temperature,pH 1.5,and time 30 s.