Effect of TiO2 addition on the crystallization of Li2O–Al2O3–4SiO2 precursor powders by a sol-gel process

Abstract

The activation energy for crystallization of β-spodumene in TiO2 added Li2O–Al2O3–4SiO2 (LAS) precursor powders by a sol-gel process was studied by using isothermal and nonisothermal methods. Nonisothermal kinetics for the LAS precursor powder system were investigated using differential thermal analysis (DTA) and quantitative x-ray diffraction (XRD) analysis. The rate of crystallization of LAS precursor powders decreased as the TiO2 content increased. For samples with addition of 0, 5.0, and 10.0 wt% TiO2, the activation energies for crystallization by DTA evaluation were 165.06, 194.46, and 205.38 kJ/mol, respectively. According to the quantitative XRD method, the values computed by the Johnson–Mehl–Avrami equation were 162.54, 189.42, and 196.14 kJ/mol, respectively. The values obtained by isothermal and nonisothermal kinetic methods from DTA and XRD analyses were in good agreement. The growth morphology parameters were 0.59, 0.70, and 0.76, respectively, for the LAS precursor powder with TiO2 addition of 0, 5.0, and 10.0 wt%, showing a rodlike growth. In the LAS precursor powder system, TiO2 did not act as the nucleative agent.