Silicon-Rich Corner of the Yb–Pt–Si Ternary System at 850°C

We have studied phase equilibria in the silicon-rich part of the Yb–Pt–Si system. To this end, 22 alloys were prepared by a standard arc-melting process in an argon atmosphere and annealed at a temperature of 850°C. Physicochemical characterization of the samples included electron microscopy, X-ray microanalysis, X-ray diffraction, and differential thermal analysis. We have confirmed the existence of four previously known intermetallic compounds: YbPtSi, YbPt2Si2, Yb3Pt4Si6, and Yb2Pt3Si5. In addition, three new phases have been identified: YbPtSi2, Yb33Pt17Si50, and Yb11Pt33Si56. The structure type of the YbPtSi2 compound has been determined. We present statistical crystallographic data for the ternary phases and describe phase equilibria in the region studied in the 850°C isothermal section of the Yb–Pt–Si phase diagram.