This study investigated the characteristics of the intermetallics that appear in Sn-Zn-Ag solder alloys, particularly their behavior in molten solder during cooling and remelting. The results indicated that the intermetallics, which deplete the Zn-rich phase, were present in the form of inhomogeneous dendrites and consisted of two intermetallic phases, ε-AgZn3 and γ-Ag5Zn8. These Ag-Zn intermetallics formed as the primary dendrites upon cooling from temperatures slightly below 300°C. These intermetallics transformed into coarse nodules with a stable, high Ag-content phase when isothermally heated at 250°C. These massive intermetallic particles tended to settle at the bottom of the melt due to low buoyancy. Isothermal heating at slightly above 300°C resulted in the rapid melting of these intermetallics. Subsequent quenching caused numerous fine dendritic intermetallics to form throughout the solder.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering