Synthesis and characterization of alumina nano-powders by oxidation of molten aluminium in a thermal plasma reactor: Comparison with theoretical estimation

Alumina nano-powders are formed in a thermal plasma reactor by in-flight reaction of micron-sized aluminium powders with atmospheric oxygen. Commercially available micron-sized aluminium powders are fed into the plasma jet using argon as a carrier gas. During in-flight, the particles are vaporized and get reacted with atmospheric oxygen. The reacted vapor nucleates and condenses on the water-cooled walls of the reaction chamber. Due to fast quenching, nanosized alumina particles were formed. The particles were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron micrograph (TEM) and EDX. A simple model is developed and the particle size is compared with the experimental results. The theoretical estimation for the particle size is in well agreement with experiment result.