某些有机添加剂对硫酸-酒石酸盐溶液中电沉积Cu-Zn合金的作用

研究了以酒石酸钾钠、柠檬酸三钠作为络合剂的酸性硫酸盐溶液中的Cu-Zn合金镀层。探讨了电流密度、pH、温度对镀液分散能力和镀层组成的影响。在本实验条件下,添加剂的加入可以使镀液具有较好的分散能力和较高的电流效率。实验发现,在所研究的各种添加剂中,糖精、苯酚是加速剂,而硫脲、甘油是阻化剂。采用动电位极化和电化学阻抗谱方法,测定了Cu-Zn合金镀层在NaCl(φ=3.5%)溶液中的耐蚀性能。采用扫描电镜研究了添加剂对控制沉积质量的微妙作用。X-射线衍射分析表明,合金镀层的相结构是正交晶。在上述研究的基础上,提出了Cu-Zn合金电沉积的最佳组成和工艺控制参数。

Actions of certain organic additives on Cu-Zn alloy electrodeposition from sulfate-tartrate solutions

Cu-Zn coatings obtained by electrodeposition from acidic sulphate solutions containing sodium potassium tartrate and trisodium citrate as the complexing agents have been studied.The effects of current density,pH and temperature on the throwing power of the bath as well as their effect on the alloy composition were evaluated.The solution affords good throwing power and current efficiency in presence of the additives under the experimental conditions.Of the different additives tried saccharin and phenol are found to be accelerators while thiourea and glycerine are retarders on the electrodeposition processes.The Cu-Zn deposits obtained with the additives have also been examined for their corrosion resistance behaviour in 3.5% NaCl solution medium through potentiodynamic polarization and electrochemical impedance spectroscopy techniques.The subtle role played by the additives in controlling the quality of the deposit has been studied using scanning electron microscope.The x-ray diffraction analysis revealed that the phase structure of alloy is an orthorhombic crystal.Based on the above studies,the optimum composition of the bath and the controlling variables for the Cu-Zn deposition are predicted.