The phase diagram of the Sr-Si system

Description

The phase diagram of the Sr–Si system has been investigated across almost the whole composition range (0–75 at.% Si) using differential thermal analysis (DTA), metallographic analysis, X-ray diffraction and electron microscopy. Four intermediate phases exist: Sr2Si (PbCl2-type), Sr5Si3 (Cr5B3-type), SrSi (CrB-type) and the dimorphic SrSi2 compound. The low-temperature form alpha-SrSi2 is cubic, SrSi2-type, and the high-temperature form beta-SrSi2 is tetragonal with the alpha-ThSi2 structure-type. For this last phase a solid solubility range, from about 62.0 to 66.7 at.% Si, has also been found. Four eutectics occur in the system: at about 3 at.% Si and 745 ◦C, 44 at.% Si and 1110 ◦C, 61 at.% Si and 1055 ◦C, 74 at.% Si and 1045 ◦C.

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