电流密度对甲基磺酸盐电沉积亚光锡的影响

Effects of Current Density on Electrodeposited Matt Tin in Methanesulfonate Electrolytes

在甲基磺酸盐电镀溶液中进行恒电流电沉积亚光锡镀层实验,考察电流密度对镀液极化性能、阴极过电位、电流效率、沉积速率及镀液分散能力的影响。利用SEM和XRD分析不同电流密度所得锡镀层的表面形貌和结晶取向。结果表明:随着电流密度增大(0.5～4A.dm-2),镀液的阴极极化增大,电流效率先增加后降低,沉积速率不断加快,但镀液分散能力有所下降;晶体由"向上生长"模式逐渐转变为"侧向生长"模式,择优取向由(321),(431)晶面转变为(112),(332)晶面;添加剂吸附在晶体表面,降低了被吸附晶面的表面自由能,使这些晶面的生长速率下降,从而改变了镀层择优取向和晶体生长的方式。

The effects of current density on cathode polarization,overpotential,deposition efficiency,deposition rate,throwing power,surface morphology and crystallization orientation in stannous methanesulfonate baths were studied using constant current polarization,scanning electron microscope and X-ray diffraction patterns.The results showed that,the cathode polarization and deposition rate increased,throwing power decreased,deposition efficiency initially increased and then decreased with the increasing of current density（0.5-4A·dm-2）.Increase in current density made the tin electro-crystallization varied from outward to lateral growth modes and crystallization orientation varied from（321） and（431） to（112） and（332） crystal faces.The additives adsorb onto crystal faces,the surface energies and growth rate decreased,preferred orientations and growth modes could be modified.