High-temperature corrosion of Sn–Bi–Zn–Ga alloys as heat transfer fluid

Abstract

The new heat transfer alloy is highly reactive at high temperatures, and the corrosion of the container material determines the service life of the heat transfer system. The high-temperature corrosion of Sn–Bi–Zn–Ga alloys as heat transfer fluid was investigated. The microstructure and elemental distribution were studied by field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS). The thermal properties before and after corrosion were studied by differential scanning calorimetry (DSC). The results show that the corrosion kinetics of the studied materials follows the parabolic law and the thermal properties after corrosion are improved. Ga significantly improves the thermal conductivity. 316 stainless steel exhibits excellent corrosion resistance due to its high Cr and Ni contents. Corrosion mechanism analysis shows that the oxidation of Ga has a smaller Gibbs free energy, and an oxide forms at the corrosion interface to prevent dissolution corrosion and oxidative corrosion of the container material.