The temperature and location of the invariant eutectic point at 403 °C in the zinc-rich corner of the Al–Sb–Zn system was determined. However, the experimentally determined temperature was found to be lower than the thermodynamically predicted one. Differential thermal analyses, differential scanning calorimetry, and quantitative microstructural analyses were used to determine this specific reaction. The determined ternary eutectic reaction, L → α-Sb2Zn3 + AlSb + η-Zn, represents the last solidification path in the phase region of Sb–AlSb–Zn. Before a ternary eutectic reaction takes place, another reaction is also possible near the Sb–Zn binary system, a quasi-peritectic reaction at 455 °C: L + β-Sb2Zn3 → AlSb + α-Sb2Zn3. A scanning electron microscope equipped with an energy-dispersive spectrometer was used for the microstructural analyses. The phase identification was conducted with X-ray diffractometry. The experimental data were compared to the thermodynamic predictions made with the CALPHAD method using the SSOL4 database.
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