The Cu–Sn System: A Comprehensive Review of the Crystal Structures of its Stable and Metastable Phases

Abstract

The present works assesses the knowledge concerning the crystal structures of phases in the Cu–Sn system having their high relevance due to their occurrence in bronze alloys and soldered systems. The crystal structures of the terminal solid solution phases α-Cu and β-Sn and of the stable main intermediate phases β, γ, ε-Cu3Sn, δ-Cu41Sn11, ζ-Cu10Sn3, η-Cu6Sn5 and η′-Cu6Sn5 and some metastable phases appear to be well established in the literature, but details can be intriguing. This paper attempts to review apparently or truly contradictory structure models derived from experimental diffraction data for the different phases, revealing limiting knowledge in some cases. These results are also analyzed regarding the results of first-principles calculations making use of various model structures. The review is also used to highlight exemplarily problems, which can be experienced upon widespread, “routine” means of phase identification, in particular x-ray diffraction (on polycrystalline specimens) and electron backscatter diffraction.

Machine learning search for stable binary Sn alloys with Na, Ca, Cu, Pd, and Ag

“…In our recent work, 130 we analyzed the thermodynamic stability of the previously reported phases at and near the 3 : 1 composition and found hP8 to have the lowest energy at T = 0 K. The most recent comprehensive review of the Cu–Sn system was compiled by Leineweber. 131…”

“…In our recent work, 130 we analyzed the thermodynamic stability of the previously reported phases at and near the 3 : 1 composition and found hP8 to have the lowest energy at T = 0 K. The most recent comprehensive review of the Cu-Sn system was compiled by Leineweber. 131 The binary system has found several technological applications due to the excellent mechanical and electronic properties of Cu-Sn intermetallics. The high melting temperature, electrical conductivity, resistance to electromigration, and other beneficial characteristics have made the Cu 3 Sn and Cu 6 Sn 5 compounds prime candidates for Pb-free interconnects in high-performance electronic devices.…”

“…It is worth noting that Leineweber pointed out a large variance of E(Z) À E(Z 0 ) values reported in several DFT studies (from À94 meV per atom to 360 meV per atom) and their discrepancy with the measured values (up to 4.5 meV per atom). 131 Our proposed approach of estimating the Z-Z 0 transition temperature highlights the importance of including the entropic terms in the evaluation of the free energy difference. The application of pressure reduces the number of viable ground states down to two at the 3 : 1 and 1 : 2 compositions as shown in Fig.…”