Correlation between thermal diffusivity and activation energy of ordering of lead free solder alloys Sn_65−xAg₂₅Sb₁₀Cu _x rapidly solidified from molten state

Abstract

Internal friction Q⁻¹, thermal diffusivity D_th, and thermal properties of the melts of Sn_65−xAg₂₅Sb₁₀ Cu _x (0–2.5 wt.%) solder alloys are investigated and studied by means of vibration resonance technique and calibrated differential thermal analysis respectively. The thermal analysis technique is used to measure the temperature dependence of the specific heat, C_p, the solidus temperature, T_s, the liquidus temperature T₁, and the activation energy of ordering U. It is found that T_s and T₁ show strong dependence on copper content. The activation energy of ordering U show critical dependence on the amount of the copper added. A typical dependence of D_th and U for all studied alloys is obtained. The formation of intermetallic compound of AgSb and Sb phases in the range of composition investigated causes a pronounced increase in the electrical resistivity.