Comparative analysis of microstructural evolution and functional enhancements in Sn–35Bi solder alloy reinforced with Al2O3, TiO2, ZnO, and CuO nanoparticles

Purpose This study aims to investigate the effects of various nanoparticle additions of Al2O3, TiO2, ZnO and CuO on the structural, thermal, mechanical, electrical and wettability properties of binary Sn–35Bi solder alloys for high-performance applications. Design/methodology/approach In this study, nanocomposite Sn–35Bi–1X solder alloys (X = 0, Al2O3, TiO2, ZnO and CuO) were synthesized via the melt-spinning technique. The structural properties were examined using X-ray diffraction (XRD) and high-resolution transmission electron microscopy, while scanning electron microscopy was used to examine the surface morphology features of the alloys. Findings XRD analysis confirmed the formation of ß-Sn and Bi-rich phases as the primary constituents, with increased peak intensities observed upon TiO2 NPs addition. The TiO2 NPs, acting as nucleation catalysts, promoted crystallite growth, which aligns with the observed increase in mechanical performance; specifically, the average values of Young’s modulus (E) and Vickers hardness (Hv) increased to 379.33 MPa and 23.06 MPa, respectively, representing a notable improvement compared to the unreinforced alloy. Differential scanning calorimetry showed a slight increase of approximately 3.31°C in the melting temperature of the NPs-reinforced alloys compared to the base Sn–35Bi alloy. In addition, incorporating CuO NPs decreased the wetting angle by approximately 22.31°, accompanied by a 64% enhancement in the wetting area compared to the TiO2-reinforced sample. The electrical resistivity of the Sn–35Bi–1CuO NPs solder alloy was reduced by 35.4% compared to the unreinforced Sn–35Bi alloy. Originality/value This work evaluates the impacts of Al2O3, TiO2, ZnO and CuO NPs on Sn–35Bi solder microstructure and other physical characteristics.