Correlation between thermal diffusivity and activation energy of ordering of lead free solder alloys Sn_(65-x)Ag_(25)Sb_(10)Cu_(x) rapidly solidified from molten state

摘要

Internal friction Q~(-1), thermal diffusivity D_(th), and thermal properties of the melts of Sn_(65-x)Ag_(25)Sb_(10) 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 T_(1), and the activation energy of ordering U. It is found that T_(s) and T_(1) 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.