The effects of pre-heating and sintering temperature on the sol-gel synthesis of mullite nanoparticles

Abstract

The aim of this study was to synthesize the mullite nanoparticles by sol-gel method using tetraethylorthosilicate (TEOS) and aluminum nitrate nonahydrate (ANN) as the precursors. The effects of the pre-heating process and sintering temperature on the structure of the synthesized powders were characterized by thermal analysis, x-ray diffraction (XRD) and scanning electron microscopy (SEM) images. Thermal analysis and XRD results showed that the crystallization temperature of the mullite phase was significantly decreased owing to application of pre-heating. The pre-heating process led to disappearances of the Al-Si spinel phase in the XRD pattern of the samples. Moreover, the SEM images of the samples demonstrated that by applying pre-heating, the growth type of mullite phase was changed from isotropic growth to the anisotropic one.