The synthesis of Sn-3.5Ag alloy nanosolder was investigated by chemical reduction method. In this method, chemical precipitation was achieved by using sodium NaBH₄ as a reducing agent and PVP (poly-m-vinyl 2- pyrrolidone) as a stabilizer. The experimental results obtained with different amounts of NaBH4 and PVP were compared. X-ray diffraction (XRD) patterns revealed that Ag₃Sn was formed due to the successful alloying process. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) demonstrated a change in the morphology of Sn-3.5 Ag alloy nanosolder with increase in the PVP content in the bath. The size of the nanoparticles ranged from 300 to 700 nm. The nanosolder/nanoparticles were thus synthesized successfully under controlled and optimized chemical reduction process

The nanoparticles of tin-silver solder, Sn-3.5Ag, of necklace geometry were made in a swirl batch. It was found that the addition of the element, Ag, did not vary the microstructure of the solder matrix, but Ag simply diluted into the Sn matrix randomly. The swirl flow facilitated the formation of particles with different sizes. It was found that the size distribution of the nanoparticles was strongly related to the height in the swirl batch. In addition, the aggregation of the nanoparticles was explored and the dispersion of the nanoparticles was achieved by adjusting the pH value of the solution near the neutral value