Interfacial reaction between an amorphous Cu-Ag-Ce alloy and Sn solder

摘要

The interfacial reaction behavior between the melt-spun, amorphous 54.8 at% Cu-39.6 at% Ag-5.6 at% Ce alloy andthe pure Sn solder was investigated at 240℃ and 180℃ andwas compared with that between the crystalline alloy, obtained by acrystallization treatment of the amorphous alloy, and the Sn solder.The amorphous and crystalline alloys showed no qualitativedifference in reaction behavior at 240℃. The reaction zone with alayered structure of Cu6Sn5/ Ce5Sn3/ Cu6Sn5 + Sn (1)1 (Cu-Ce)+Sn(I) grew fast as the liquid Sn dissolved preferentially Ag ofthe alloys. During the annealing of the Sn-wetted alloys at 180℃for 100 hours, the reaction zones formed in the amorphous andcrystalline alloys showed similar layered structures but the growthbehavior of the reaction zone was significantly different: areaction-limited growth in the amorphous alloy and a diffusion-limited growth in the crystalline growth. The difference can be at-tributed to the fact that the bulk diffusivity of Sn in the amorphousalloy is much lower than the grain boundary diffusivity of Sn in thecrystalline alloy