Partial isothermal section of the Dy-Co-Ga ternary system at 500°C

Abstract

Abstract The partial isothermal section of the Dy–Co–Ga ternary system (below 33.3 at.% Dy) at 500 °C was investigated and constructed mainly using X-ray powder diffraction analysis with the aid of scanning electron microscopy. The 8 binary compounds, CoGa, CoGa3, Dy2Co17, Dy2Co7, DyCo3, DyCo2, DyGa3 and DyGa2, and the 9 previously reported ternary compounds DyCoGa (γ), Dy5Co12Ga3 (δ), DyCo3Ga2 (κ), Dy6Co7Ga21 (ν), Dy2CoGa8 (ο), Dy2Co3Ga9 (θ), DyCoGa5 (ρ), DyCo5Ga7 (λ) and Dy2Co13 – 11Ga4 – 6 (α) have been confirmed in the partial isothermal section at 500 °C. Five new ternary compounds, DyCo4.41 – 3.35 · Ga0.59 – 1.65 (β), DyCo1.33Ga0.67 (∊), DyCo0.67 – 0.35Ga1.33 – 1.65 (η), DyCo0.25 – 0.15Ga1.75 – 1.85 (ϕ), Dy3Co3Ga8 (μ), were found in this partial isothermal section. The structures of all compounds have been confirmed or determined. The nine compounds, Dy2Co17, Dy2Co13.5 – 9.10Ga3.5 – 7. 6 (α), DyCo4.41 – 3.35 · Ga0.59 – 1.65 (β), Dy2Co7, DyCo3, DyCo2. 55 – 1.8Ga0. 45 – 1.2 (δ), DyGa2, DyCo0.67 – 0.35Ga1.33 – 1.65 (η) and DyCo0.25 – 0.15 · Ga1.75 – 1.85 (ϕ), form solid solutions by the substitution of Ga atoms for Co atoms in the compounds. The solid solution ranges for these solid solutions have been obtained from their powder X-ray diffraction data.