Effect of doping Si3N4 nanoparticles on the properties and microstructure of Sn1.0Ag0.5Cu solder

This study focused on the comprehensive performance of Sn1.0Ag0.5Cu (SAC105)-Si3N4 solder joints. Changes in the wettability and thermal properties of this solder were mainly studied comprehensively, along with observations on the microstructure, intermetallic compounds (IMC) and mechanical properties of solder joints. The incorporation of Si3N4 nanoparticles (NPs) in SAC105 solder demonstrated negligible effects on its melting point, with slight fluctuations in the degree of undercooling. When the adding amount reached 0.4 wt%, the spreading area was the largest, 82.06 mm2, which was 26.67 % more than that without Si3N4 NPs. At the same time, the minimum contact angle was 18.6 degrees. Afterwards, the moderate addition of Si3N4 could significantly refine the solder joint microstructure and the IMC layer grain. Meanwhile, the highest shear strength of 29.55 MPa was achieved, reaching a significant 21.78 % enhancement in the shear strength compared to pure SAC105 solder/Cu joints. The solder joints attained a hardness value of 14.07 HV, marking a 9.6 % enhancement over SAC105 solder joints. Evidently, the judicious inclusion of Si3N4 NPs with SAC105 solder enhances the overall performance characteristics of both the solder alloy and solder joints.