Phase Equilibria of the Cu-Si-Sn System at 700 and 500 degrees C

作者：Song, Yuanyuan^*; Su, Xuping; Liu, Ya; Peng, Haoping; Wu, Changjun; Wang, Jianhua

来源：Journal of Phase Equilibria and Diffusion, 2015, 36(5): 493-502.

DOI：10.1007/s11669-015-0405-3

• Cu-Si-Sn system
• intermetallics
• phase equilibria Sn-based solder

Intermetallic compounds formed in solder joints have a substantial effect on reliability. Because Sn-based alloys are alternatives to lead-containing solders, phase equilibria of the Cu-Si-Sn system were investigated for quenched samples annealed at 700 and 500 A degrees C for 30 days. Nine three-phase equilibria were well established at 700 A degrees C, and a previously unknown ternary tau phase with a possible homogeneity interval in the range Cu76Sn7.8Si16.2-Cu85Sn7.6Si7.4 was found for the first time. The tau phase has a hexagonal structure with a = 8.012 nm and c = 5.04 nm. Six three-phase regions were identified in the isothermal region at 500 A degrees C. In contrast with the isothermal region at 700 A degrees C, the new ternary tau phase was not observed at 500 A degrees C. The solubility of Si in epsilon-Cu3Sn decreases from 12.8 to 1.4 at.%, and only small variations occur in the homogeneity ranges of eta-Cu3Si and gamma-Cu5Si.

• 出版日期2015-10
• 单位常州大学