Characterization of the Sn78Bi22 alloy as an environmentally friendly lead-free solder
- 1 January 2026
- conference paper
- Published by Centre for Evaluation in Education and Science (CEON/CEES)
- No. Conference,p. 410-416
Abstract
The development of reliable lead-free solder alloys remains essential for applications in the electronics industry. This paper investigates the mechanical, electrical, and microstructural properties of a Sn78Bi22 solder alloy. The alloy was prepared by melting and casting, followed by a homogenization heat treatment. Tensile testing, Vickers microhardness measurements, electrical conductivity testing, and SEM/EDS microstructural analysis were performed at room temperature. The investigated alloy exhibited enhanced ultimate tensile strength (~93 MPa) and microhardness (45.5 HV0.05) compared with pure Sn, while electrical conductivity decreased to 5.4 MS/m. These changes were attributed to solid-solution strengthening, grain refinement, and the formation of a Bi-rich secondary phase, which also promoted brittle fracture during tensile testing. Microstructural observations revealed a Sn matrix with finely distributed Bi-rich phases, particularly along grain boundaries. The results contribute additional experimental data on the mechanical, electrical, and microstructural characteristics of non-eutectic Sn-Bi solder alloys.Keywords
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