Microstructural, mechanical, and wear properties of Sn-based solder alloy modified with graphite nanoparticles

This study investigated the microstructural, mechanical, and wear properties of the Sn-2.5 wt%Ag-0.4 wt%Cu-1.0 wt%In (SAC-1.0In) solder alloy including nano-graphite (0.6-1.2 wt%). The microstructural characteristics of several samples were investigated using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive x-ray spectrometry (EDS), electron probe microanalysis (EPMA), x-ray diffraction (XRD), and x-ray photoelectronic spectroscopy (XPS). The results of this study revealed that the presence of nano-graphite particles stimulated the production of distinct intermetallic compound phases (IMC) identified as Ag3Sn, Cu6Sn5, and gamma-InSn4. These IMCs are uniformly dispersed throughout the matrix. The results showed that the addition of nano-graphite particles did not significantly alter the morphology of the microstructure but reduced the particle size of these IMCs. This refining of precipitated IMC particles resulted in considerable improvements in the material's mechanical properties. The wear properties of both unreinforced matrix and graphite composites were investigated utilizing a pin-on-disc tribometer. The addition of 0.6, 0.9, and 1.2 wt% graphite nanoparticles decreased the sliding wear rate. It is worth noting that the current study is deemed unique and novel in terms of total strain percent behavior as graphite content increases.