Resonance character of polymorphic transformations for the phase transition α'L → β'L → βCa2SiO4

Experimental results are presented showing that rapid cooling of dicalcium silicate is accompanied by delay of structural processes, which leads to a decreasing in temperature of the phase transition α'L → Ca2SiO4. As starting materials, nepheline ore and limestone were used. In preparing the charge, the dosage of starting components was calculated for obtaining a molar ratio of CaO/SiO2 = 2.0. From the charge, the series of samples was prepared. Each of the samples was sintered to t = 1250°C with subsequent keeping of the material at this temperature for 30 min. Then the samples were subjected to rapid cooling in air to t = 750, 650, 550, 450, 350, 250, 150, and 25°C. By means of quantitative X-ray powder diffraction analysis using a DRON-3 setup, the content of α'L and β-Ca2SiO4 was determined in the samples. The data allow us to suppose the occurring polymorphic transformations in dicalcium silicate have a resonance character. © Allerton Press, Inc., 2007.