阳极Sn含量对焦磷酸盐电镀低锡Cu-Sn合金层性能的影响

为改善焦磷酸盐电镀Cu-Sn合金层的耐蚀性能差、镀速慢、结合力差等问题,用失重试验、形貌成分分析及电化学技术等方法,研究了阳极中Sn含量对焦磷酸盐电镀Cu-Sn合金层的沉积速率、腐蚀速率、腐蚀过程和微观形貌等的影响。结果表明:当阳极中Sn含量(质量分数)为25%时,Cu-Sn合金镀层的沉积速率较大6.32mg/(cm2·h)],镀层中Sn含量为5.80%,属于低锡青铜,镀层耐蚀性好,在5%H2SO4溶液中的失重腐蚀速率最小,为0.011 8 mg/(cm2·h),腐蚀电流密度较小(84.7μA/cm2),腐蚀电位最正(-0.405 V),腐蚀倾向最小;CuSn合金镀层的包状物颗粒大小均匀、排列紧密、无明显的表面缺陷,镀层与基体结合良好。

Influences of Anode Sn Content on Properties of Electroplating Cu-Sn Alloy Coating in Pyrophosphate Bath

In order to improve the corrosion resistance,poor deposition rate and binding force of the pyrophosphate electroplating Cu-Sn alloy coating,the influences of anode Sn content on the deposition rate,corrosion rate,corrosion process and microstructure of Cu-Sn alloy coating were investigated by weight loss test,SEM and electrochemical methods.Results showed that when Sn content in the Cu-Sn alloy anode was 25％,the high deposition rate (6.32 mg· cm-2 · h-1,) was obtained with low Sn content of 5.80％.The weight loss corrosion rate was low (0.011 8 mg · cm-2 · h-1) in 5％H2SO4 solution with the low corrosion current density (84.7 μA/cm2) and high self-corrosion potential (-0.405 V),and the Cu-Sn alloy coatings presented the best anti-corrosion property.In addition,alloy coating became dense,uniform and defect-free,and meantime the binding force was good.