The experimental phase equilibria studies of the Ni-Sn-S system

Abstract

The Ni-Sn-S system can be used to describe the chemistry of Ni-based battery materials, printed circuit boards, and other waste from electrical and electronic equipment. Therefore, understanding the phase equilibria of the Ni-Sn-S system is essential for managing and recycling these metals effectively. This study was focused on the high-temperature phase equilibria in the Ni-Sn-S system. The experimental techniques used in the present study included high-temperature equilibration and quenching, followed by direct measurement of compositions of phases present in the samples using the electron probe X-ray microanalysis (EPMA). Primary phase fields of the following phases were experimentally characterized in the temperature range from 500 to 1100 °C: two mattes (NiS- and SnS-rich), liquid metal, FCC-Ni, Ni3Sn (high- and low-temperature), Ni1+xSn, Ni3Sn4, Sn-rich β-Ni3S2, Ni1-xS, NiS2, SnS, Sn2S3, SnS2, and Ni3Sn2S2. Incongruently melting Ni3Sn2S2 was the only ternary compound identified to be present at the liquidus conditions. Invariant reactions and saddle points present at the liquidus conditions were accurately identified. This study was a part of the integrated experimental and thermodynamic modeling study of phase equilibria in the Cu-Sb-Sn-Ni-S-Fe-As matte/speiss/liquid metal system. It is a small part of the 20-component gas/oxide liquid/matte/speiss/liquid metal/salt/solids system in support of the metallurgical operations