| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Electronic Packaging and Interconnection Materials II
|
| Presentation Title |
Surface Precipitation and Growth Mechanisms of Bismuth Particles in Sn-Bi and Sn-Ag-Cu (SAC)-Bi Solder Alloys |
| Author(s) |
John Wu, Amey Luktuke, Eshan Ganju, Nikhilesh Chawla |
| On-Site Speaker (Planned) |
Nikhilesh Chawla |
| Abstract Scope |
Bismuth (Bi) is a commonly added alloying element to Pb-free solders to reduce the solder alloy’s melting temperature and enhance joint strength. Our previous work on Bi related solder alloys has proven that precipitation is driven by surface diffusion, and we have continued this work on binary Sn-7Bi to investigate the precipitation mechanisms of different morphologies of Bi particles. Globular and plate-like Bi precipitates nucleate at different interfaces (particle/matrix or grain boundaries) and have vastly different coarsening mechanisms. We also present an extension of our study to the SAC305-7Bi system, where we combine our findings in the binary Sn7Bi system with the SAC305 alloy. The microstructure was characterized with Electron Backscatter Diffraction (EBSD) and Energy-dispersive spectroscopy (EDS), followed by time-resolved imaging using scanning electron microscopy (SEM). Correlation of bismuth precipitation to the diffusion mechanisms at the grain boundaries, Cu6Sn5-Sn and Ag3Sn-Sn boundary, and bulk will be discussed. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, Electronic Materials, |