| Popis: |
In electronic applications, solder joint is exposed to thermo-mechanical load originating from the coefficient of thermal expansion (CTE) mismatch with the component and the printed circuit board it is joining. Within the solder joint, local CTE mismatch exists among various microstructural constituents as well as between grains of thermally anisotropic tin in a single polycrystalline phase. This study aims to investigate the effects of cooling rate and isothermal aging on the microstructure of 99.3Sn0.7Cu solder. The cooling rates were air cooling, 2°C/s cooling, and 7°C/s cooling. The aging was done at 150°C for different aging durations, i.e., 25, 125, and 225 hours. After soldering the tin-copper material, the thickness of intermetallic compound formed was higher for furnace cooling compared to air cooling. There was no significant difference between 2°C/s and 7°C/s furnace cooled solders. It was also found that the thickness and grain size of intermetallic compound formed was higher with increasing aging duration. |
