Nano α‐Al ₂ O ₃ Powder Preparation by Calcining an Emulsion Precursor

Abstract

An experimental study has been conducted to evaluate the formation of nano α‐Al 2 O 3 under various conditions, such as different calcining temperatures and emulsion ratios of aqueous aluminum nitrate solutions and oleic acid with a high‐speed stirring mixer. Four batches of the precursor powders were calcined at three different temperatures of 1000°, 1050°, and 1100°C for 2 h and a terminal product of nano α‐Al 2 O 3 powders was obtained. The products have been identified by X‐ray diffraction (XRD), specific surface area measurement scanning electron microscope, and transmission electron microscope (TEM). The XRD results show that the phase of powders is determined to be α‐Al 2 O 3 , indicating that the overall process has been effective. The optimum calcination temperature of the precursor powder for crystallization of nano α‐Al 2 O 3 was found to be 1000°C for 2 h. The TEM image indicates that the particle grains have a sub‐spherical shape with a mean size of 50–100 nm.