Effect of Zn additions on microstructure and properties of near eutectic sn-3.0ag solder alloy

Abstract EN

In this study, the effect of Zn concentration on microstructure refinement, melting behavior, electrical resistivity and mechanical properties of near-eutectic Sn–3.0Ag alloy has been investigated.

The addition of 1%Zn is found to contribute to the refinement of mostly eutectic Ag3Sn IMC phase and suppressed the formation of β-Sn dendritic structure.

The microstructure analysis also revealed that a new ξ–AgZn and γ– Ag5Zn8 fine particles containing large amount of Zn were generated.

ξ–AgZn and γ–Ag5Zn8 phases are observed to enlarge with a high Zn of concentration.

Although the pasty range slightly increased, Zn addition can effectively reduce the onset temperature and undercooling.

Moreover, it was found that the Sn–3.0Ag–1.0Zn alloy undertakes with the compromise between low electrical resistivity, high tensile strength and ductility.

Particle strengthening by Ag3Sn phase, β-Sn grain refinement, and the stress concentration along both types of Zn-rich IMC particles contributed more significantly to the electrical and mechanical properties of the investigated solder systems.