Influence of Ammonium Chloride on Preparation of α-Al_2O_3 Nanopowder by Thermal Decomposition of Ammonium Aluminum Carbonate Hydroxide

Nanometer ammonium aluminum carbonate hydroxide (AACH) was prepared by precipitation method using NH4Al(SO4)2 and NH4HCO3 as raw materials.α-Al2O3 was prepared by thermal decomposition of AACH. The structural properties of AACH and α-Al2O3 were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the phase transformation temperature of α-Al2O3 could be decreased using NH4Cl as additive. The higher the mass fraction of NH4Cl is, the finer the powder is. The well dispersed α-Al2O3 nanopowder was obtained via thermal decomposition of AACH with 10% NH4Cl at 1150 ℃ for 1 h.