Preparation and characterization of alpha alumina nanoparticles by in-flight oxidation of flame synthesis

•Flame synthesis is a compact approach for the synthesis of metal oxide nanoparticles.•Single phase alumina nanoparticles have been synthesized from commercial aluminium powders.•Spherical particle is confirmed by TEM analysis.•Photoluminescence study is discussed elaborately. Alpha alumina nanoparticles were synthesized from micron-sized commercial aluminium powders by in-flight oxidation of flame synthesis. The synthesized alumina nanoparticles were characterized using X-ray diffraction (XRD) and α phase alumina was confirmed. The average grain sizes were estimated to be 98nm using Scherer’s formula. The formation of alumina nanoparticles was identified by scanning electron microscopy (SEM). Transmission electron microscopy (TEM) study shows the different sized spherical nanoparticles ranging from 70nm to 150nm. The energy dispersive X-ray analysis (EDAX) confirms the presence of aluminium and oxygen in the α-Al2O3 nanoparticles. The Photoluminescence spectrum of α-Al2O3 nanoparticles reveals the presence of a large amount of oxygen vacancies.