Precise characterization of polymorphs of tricalcium silicate using X-ray diffraction

T₁, T₃ and M₃ polymorphs of the tricalcium silicate (C₃S) were prepared at 1500°C via doping of MgO at 0, 0.6% and 1.5% (mass fraction). The diffraction data of the samples were obtained by X-ray diffractometer with different resolutions. The results show that the fingerprint patterns of the X-ray powder diffraction for the C₃S polymorphs are identical, which can be used to investigate the polymorphism of C₃S. The diffraction peaks for C₃S polymorphs are broadened and vague, and some peaks are overlapped under the measurement condition of a lower resolution (full width at half maximum (FWHM)≥0.129°) and K_a2 radiation. When the data are collected at a higher resolution (FWHM≤0.072°) without K_a2, the patterns are identical to distinguish the polymorphism of C₃S.