SnCu钎料合金镀层钎焊连接机理及界面反应

通过在LD31铝合金表面电刷镀Ni，Cu后再沉积SnCu钎料合金镀层的钎焊实验，研究了钎料镀层的连接机理及界面反应，改进了可降低Ni层应力的电刷镀镀Ni液的配方，开发出适合镀层钎焊的SnCu钎料合金镀液，钎焊时钎料润湿为附着润湿，研究了在300℃钎焊时焊缝界面金属间化合物的生长规律，结果表明：焊缝中Cu-SnCu界面处生成了球状和棒状的Cu6Sn5金属间化合物；拉伸时焊缝主要沿着SnCu金属间化合物和富Sn相之间的界面断裂。

BONDING MECHANISM AND INTERFACIAL REACTION OF SnCu FILLER ALLOY COATING

The bonding mechanism and interfacial reaction of LD31 aluminum alloy soldered with electric brush deposited Ni, Cu and then SnCu filler alloy were studied. Ni and SnCu alloy plating baths developed in this work can decrease the stress in Ni layer. The influence of electric deposition parameters of Ni and SnCu alloy on the coating quality and subsequent solderability was analyzed. The wetting mechanism of SnCu coating in soldering process is adhesive wetting. SEM observation and XRD analysis show that a layer of sphere-like and rod-like Cu6Sn5 formed at Cu and SnCu interface, the shear strength could reach as high as 20 MPa and the joint fractured at the interface of the intermetallic compound and Sn-rich phase.