Kinetic study of crystallisation of sol-gel derived calcia-alumina binary compounds

摘要

In-situ High Temperature X-ray Diffraction (HTXRD) and Differential Scanning Calorimetric (DSC) studies were performed on a sol-gel derived binary compound of a calcia-alumina (C12A7) system consisting of calcium oxide (CaO) and aluminium oxide (Al_2O_3) in a ratio of 12:7 for in situ investigation into the phase transformations under progressively increasing thermal activation from room-temperature to 1200 °C. The crystallisation of amorphous samples formulated at room-temperature on magnesium oxide (MgO) single crystal (100) substrates was found to be complete on heat treatment at 1100 °C for 3 h. This observation was further supported by independent Fourier Transform Infrared (FTIR) and Raman Spec-troscopies. Values of 348 kJ/mol and 375 kJ/mol were estimated from Kissinger plots for activation energies of crystallisation of CaO and Al_2O_3 constituents, respectively.