Reaction mechanism and kinetic analysis of the formation of Sr2SiO4 via solid-state reaction

The kinetics for the formation of Sr2SiO4 during solid-state reaction is investigated using an isothermal method. TG/DTA and XRD analysis suggest a direct reaction between SrCO3 and SiO2 powders. The conversion ratios of the Sr2SiO4 starting materials are calculated from the weight loss. Based on the reaction kinetic isothermal analysis, Sr2SiO4 formation is corroborated as controlled by the Brounshtein-Ginstling's diffusion-controlled model. The formation process activation energy is estimated to be 139.6 kJ/mol. According to microscopic observations, the microstructures vary drastically at 830 °C, implying a reaction initiation involving reactive SrCO3 and SiO2. In view of the diffusion controlled mechanism and microstructural observations, a reaction model for the formation of Sr2SiO4 has been established.