Mechanical and Thermal Consequences of Added Phosphorus and Gallium in Lead-free Alloy Based on Bismuth and Tin

• Published in: 2021 44th International Spring Seminar on Electronics Technology (ISSE) pp. 1 - 5
• Main Authors: Kadlecova, Anna, Kralova, Iva, Vesely, Petr
• Format: Conference Proceeding
• Language: English
• Published: IEEE 05.05.2021
• Subjects: Gallium; Lead; Metals; Phosphorus; Temperature; Thermal conductivity; Tin
• ISSN: 2161-2536
• DOI: 10.1109/ISSE51996.2021.9467640

The objective of this work is to examine the mechanical and thermal properties of novel lead-free bismuth-tin solder alloys with low melting temperature, each with a different percentage of added gallium and with phosphorus as a trace element. The motivation was to determine solder alloy with decreased melting point and maintain mechanical properties of eutectic bismuth-tin solder alloy at the same time. BiSn40, BiSn40P, BiSn40Ga1, BiSn40Ga1P, BiSn40Ga3, and BiSn40Ga3P were among the analyzed solder alloys. In addition, the same properties of BiSn42 were analyzed for comparison as a reference. The thermal properties were examined by differential thermal analysis, where the melting and solidification points were determined. The Vickers micro-hardness test was conducted for the observation of mechanical attributes. Moreover, the microstructure of the alloys was observed in a scanning electron microscope. The result of this study showed that the temperature of the melting point significantly decreased in the alloy BiSn40Ga3. Also, this alloy seems to have as sufficient mechanical properties as BiSn42. Therefore, it could possibly be used as a suitable substitution for the eutectic solder alloy.