<p>The eutectic Sn-9Zn solder alloys reinforced with ZrO₂ nanoparticles, or Ni synthesized by the vacuum melting process. The crystal structure and morphology features revealed that adding ZrO₂ to Sn-9Zn reduced unit cell volume of β-Sn with a contraction in lattice parameters, which refined the crystallite size and reduced β-Sn grain size. But Ni additions do not affect the cell symmetry whereas the crystallite size and grain size were refined due to formation of Ni₅Zn₂₁ and Sn₃Ni₄Zn₃ IMCs with homogenous distribution. The electrical resistivity (ρ) and thermal conductivity was determined in relation to alloy composition at different temperatures. The temperature coefficient of resistivity (α) for Sn-9Zn was around 4.19 × 10^–4 K⁻¹ lower than the traditional Sn–Pb solders and reaching 2.35 × 10^–4 K⁻¹ for Sn-9Zn-0.3Ni, which indicated that the resistivity for Sn-9Zn is less temperature-sensitive. The hardness for Sn-9Zn was enhanced with incorporating of ZrO₂ or Ni elements. The results obtained for the&#xa0;stress exponent suggesting dispersion with strengthening mechanisms.</p>