甲基磺酸亚锡溶液中不同稳定剂的作用机制及电化学性质

Mechanisms and Electrochemical Properties of Different Stabilizers in Stannous Methanesulfonate Solution

研究了对苯二酚、邻苯二酚、间苯二酚和抗坏血酸4种稳定剂对甲基磺酸亚锡电镀液稳定性、电极极化及镀层表面形貌的影响.采用循环伏安法探究了镀液稳定性与稳定剂电化学性质的关系,通过交流阻抗和计时电位考察了稳定剂对镀液阴极极化性能的影响,分析了对苯二酚在电镀过程中的循环使用原理及对苯二酚的最佳使用浓度.结果表明,镀液的稳定性与稳定剂自身的还原能力及电化学活性之间存在重要联系,4种稳定剂对镀液稳定作用的大小顺序为对苯二酚>邻苯二酚>抗坏血酸>间苯二酚,稳定效果最好的对苯二酚可以将镀液的储存时间延长一倍;苯二酚类稳定剂可以提高锡沉积的阴极极化程度,使晶粒细化,而抗坏血酸对锡沉积起到去极化作用;对苯二酚在电镀锡过程中兼具抗氧化剂、光亮剂和整平剂的作用,镀层的耐蚀性能测试结果表明,对苯二酚的最佳浓度为1.0 g/L.

The effects of hydroquinone,catechol,resorcinol and ascorbic acid on the stability of stannous methanesulfonate plating bath,electrochemical properties and the surface morphology of the tin coating were investigated. And the relationship between the stability of the plating solution and the reducibility and electrochemical activity of the stabilizer was explored by cyclic voltammograms. The influence of stabilizer on the cathodic polarization performance of the bath was investigated by alternating current（ AC） impedance and chronopotentiometry. The principle of cyclic application of hydroquinone in electroplating process and the optimal concentration of hydroquinone were studied. The results show that there is an important relationship between the stability of the plating solution and the reduction ability and electrochemical activity of the stabilizer. The stability of the four stabilizers on the bath is in the order of magnitude： hydroquinonecatecholascorbic acidresorcinol,and hydroquinone,the best stabilizer,can double the storage time of the plating solution. Phenolic stabilizers can increase the degree of cathodic polarization of tin deposition and refine the grains,while ascorbic acid has a depolarization effect on the deposition of tin. Hydroquinone plays a role of antioxidant,brightener and leveler in the tin electroplating process. The corrosion resistance of the coating shows that the optimum concentration of hydroquinone is 1. 0 g/L.