Phase equilibria and liquidus projection determination of the Ce–Co–Sb ternary system

Abstract

The Ce-Co-Sb ternary system is experimentally investigated, including the isothermal section at 823 K and the supplementary measurements at 673 K, as well as the liquidus projection of this system. For the isothermal section at 823 K, the phase equilibria in the whole composition range are determined using the equilibrated alloys prepared by the combination of arc melting method and high frequency melting method under the protection of an argon atmosphere, in case of the volatility of Sb and the oxidation of Ce. To confirm the phase relations at 673 K from previous literature report, some phase equilibria are re-determined on the basis of supplementary experiments. Two ternary compounds, (CeCouSb2) and CeCoSb3 are observed and the isothermal sections of the Ce-Co-Sb system at 823 and 673 K are finally constructed. The solidification paths of the Ce-Co-Sb as-cast alloys are analyzed to ascertain the primarily solidified phases from liquid. Both the liquidus projection and the isothermal sections of the Ce-Co-Sb system are determined based on the microstructures, crystal structures and phase compositions determined by scanning electron microscopy, X-ray diffraction and electron probe micro-analyzer, respectively. Some phase transition temperatures of the Ce-Co rich region are determined by means of differential scanning calorimeter.