Thermodynamic Description of the Au-Sb-Sn Ternary System

Abstract

Phase equilibria and thermodynamic properties of the Au-Sb-Sn ternary system are important for the design of Au-based alloys as high-temperature lead-free solders to replace high-Pb solders. In this work, phase transition temperatures of five Sb-Sn alloys were measured using differential thermal analysis (DTA), and the temperatures of three invariant reactions were determined. Based on the measured experimental results in this work and the reported results, the Sb-Sn binary system was re-optimized using the CALPHAD method. The calculated results were in good agreement with available phase equilibria and thermodynamic data. This work was further combined with the previous assessments of the Au-Sn and Au-Sb binary systems and the present optimization of the Sb-Sn binary system to calculate the phase equilibria and thermodynamic properties of the Au-Sb-Sn ternary system, according to the reported experimental results, including thermodynamic properties and phase equilibria. The calculated liquidus projection, isothermal sections, vertical sections, as well as enthalpy of mixing and activity of Sn in liquid alloys are consistent well with the reported experimental results. A self-consistent set of thermodynamic parameters was obtained to accurately describe Gibbs energies of various phases in the Au-Sb-Sn ternary system, which would serve as a sound basis for developing a thermodynamic database of multicomponent Au-Sn-based alloy systems.

Research Progress in Corrosion Protection Technology for Electronic Components

“…Compared to the traditional lead-containing solder used, which releases toxic metal lead and may endanger human health and the environment, the lead-free solder system is more environmentally friendly and more in line with health requirements; leadfree solder is now widely used in chip packaging in the electronics industry [36]. Common types of lead-free solder include Sn-Ag-Cu, Sn-Ag, Sn-Cu, and so on [37,38]. It is worth noting that, as most of the lead-free solders used at this stage contain elements such as boron, silver, and copper, most lead-free solders have performance deficiencies compared to lead-containing solders, such as insufficient oxidation resistance [39], which makes chips encapsulated with lead-free solder systems more prone to corrosion and, thus, affects chip life.…”