| Abstract Scope |
The Co-Ge-Sb and Co-Ni-Ge systems are important thermoelectric material systems. Phase equilibrium information is fundamentally important. The phase equilibria of these two material systems were experimentally determined at 800 °C. In the Co-Ge-Sb system, eleven three-phase regions were identified: Co + ε-Co + CoSb, ε-Co + Co5Ge3 + CoSb, Co5Ge3 + Co3Ge2Sb + CoGe, Co5Ge3 + Co3Ge2Sb + CoSb, CoGe2 + Ge + Liquid, CoGe2 + Co5Ge7 + Liquid, CoGe + Co5Ge7 + Liquid, CoGe + Co3Ge2Sb + Liquid, CoSb3 + Co3Ge2Sb + Liquid, CoSb2 + CoSb3 + Co3Ge2Sb, CoSb + CoSb2 + Co3Ge2Sb. A ternary compound, Co-Sb-Ge, was also observed. In the Co-Ni-Ge system, five three-phase regions were observed: CoGe₂ + Ge + Liquid, CoGe₂ + Liquid + (Co,Ni)Ge, CoGe₂ + Co₅Ge₇ + (Co,Ni)Ge, ε(Co) + (Co,Ni)₅Ge₃ + Ni₃Ge, and ε(Co) + (Co,Ni) + Ni₃Ge. Additionally, three continuous solid solution phases were identified: (Co,Ni), (Co,Ni)Ge, and (Co,Ni)₅Ge₃. |