Supplementary measurements of the primary crystalline phases of the Co–Ni–Sb and the Co–Fe–Sb ternary systems

Some primary crystalline phases of the Co–Ni–Sb and the Co–Fe–Sb systems are studied on the basis of the crystalline structure analysis by X-ray diffraction (XRD), the microstructure observation by scanning electron microscopy (SEM), the composition determination by electron probe microanalysis (EPMA) and the phase equilibrium relations of the constituent binary systems. From the experimental measurements of the present work and the phase equilibrium relations of literature reports, the liquidus projections of the Co–Ni–Sb and the Co–Fe–Sb ternary systems are determined. There exist 6 primary crystalline phases in each of the ternary systems, which are γ(A1)–Fcc_A1, β(Co,Ni)3Sb–D03, γ(Co,Ni)Sb–NiAs, ζ(Co,Ni)Sb2–FeS2, η(Co,Ni)Sb3–CoAs3 and Sb–Rhombo_A7 in the Co–Ni–Sb system and γ(A1)–Fcc_A1, α(A2)–Bcc_A2, γ(Co,Fe)Sb–NiAs, ζ(Co,Fe)Sb2–FeS2, η(Co,Fe)Sb3–CoAs3 and Sb–Rhombo_A7 in the Co–Fe–Sb system. Two of invariant reactions are proposed, which are the eutectic reaction L → γ(A1) + β(Co,Ni)3Sb + γ(Co,Ni)Sb in the Co–Ni rich side of the Co–Ni–Sb system and the transition reaction L + γ(A1) → α(A2) + γ(Co,Fe)Sb in the Co–Fe rich side of the Co–Fe–Sb system.

Research highlights
► The liquidus projections of the Co–Ni–Sb and the Co–Fe–Sb systems are presented.
► The primary crystalline phases, mono-variant and invariant reactions are determined.
► The solidification paths of the experimental samples are studied.