Synthesis of nanophase alumina, and spheroidization of alumina particles, and phase transition studies through DC thermal plasma processing

摘要

Using a non-transferred DC plasma spray torch, nanosized alumina particles were synthesized from micron-sized aluminium particles. Irregular-shaped micron-sized alumina particles were spheroidized using the plasma spray torch. The synthesized powder particles were characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, Fourier transform infra-red (FT-IR) spectroscopy and photoluminescence (PL) spectroscopy. The synthesized alumina nanoparticles appear spherical in shape, but mostly agglomerated in the size range 30-75 nm. It was identified that the main phase is gamma-alumina with a small amount of delta-alumina. In the spheroidized alumina particles, the main phase is alpha-alumina with a small amount of gamma-alumina. The mechanism of formation of alumina and its phase change are explained in detail. (C) 2007 Elsevier Ltd. All rights reserved.