以次磷酸钠化学镀铜体系为研究对象,采用SEM、XRD、线性极化、电化学阻抗等测试方法,重点探讨了添加剂α-α′联吡啶对该体系的影响。结果表明,α-α′联吡啶能明显改善镀层外观质量,其最佳浓度为10 mg/L。适宜条件下镀层结晶均匀、细致,沉积层为立方晶系单质Cu。随着α-α′联吡啶浓度的增加,Cu阴极峰电流逐渐减小并趋于稳定;α-α′联吡啶对次磷酸钠的氧化具有抑制作用,但对Cu的溶解有促进作用,阻化了铜离子的阴极还原,降低化学镀铜的沉积速率,因而改善了镀层的质量。
Abstract: The influence of α,α′-dipyridyl on electroless copper plating with sodium hypophosphite bath was investigated using SEM,XRD,Linear Polarization and AC impedance tests.The results show that the coating quality and stability of sodium hypophosphite bath are enhanced by proper amount of α,α′-dipyridyl,and the proper amount is 10 mg/L.The coating is uniform and compact under optimal conditions,the deposition is cubic crystalline pure copper.With the presence of α,α′-dipyridyl,the cathode peak current density decreases gradually to a stable value.The α,α′-dipyridyl inhibits the catalytic oxidation of hypophosphite,but enhances the dissolution of copper electrode resulting in suppression of the reduction of cupric ion,thus the coating quality may be inproved.