Wetting behavior and interfacial reactions of Sn/Cu-xNi couples for high temperature application

The current work was carried out to understand the interfacial reactions and wetting behavior between pure Sn and Cu-xNi alloy plates (x = 0, 4, 8, 10 and 14 wt.%) at 260 °C for different durations up to 10 min. The wetting area of Sn/Cu-xNi couples increased firstly and then decreased with the increasing of Ni content, reaching a maximum at 8 wt.% Ni. Adding a certain amount of Ni to the pure Cu plate significantly accelerated the growth of interfacial (Cu,Ni)
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Sn
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intermetallic compound (IMC) and reached the fastest growth rate in the Sn/Cu-8Ni solder joint while greatly suppressed the growth of interfacial Cu
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Sn phase. Furthermore, the interfacial (Cu,Ni)
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Sn
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IMC grains formed at the Sn/Cu-Ni interfaces displayed various morphologies. The optimal wetting property and the fastest growth rate were obtained for the Sn/Cu-8Ni couple, which can remarkably decrease the bonding time and cost. Therefore, the Sn/Cu-xNi reaction couple is particularly suitable for solid-liquid interdiffusion (SLID) bonding technology for high temperature application.