Synthesis of Al2O3 nanopowders using inorganic salt and its physical chemistry

Boehmite (γ-AIOOH) powder was first prepared by Sol-Freeze Drying method using cheapAICl3.6H2O as raw materials, and then γ-Al2O3 nanopowder with the average diameter of 6umand α-Al2O3 nanopowder with the mean diameter of 30um were obtained by the calcination of theabove γ-AlOOH powder at 500 and 1100℃, respectively. The potential~pH diagrams of Al--H2Osystem at 25 and 90℃ were presented, separately. Thermodynamic analysis of the main reactionsin the process of thermal decomposition of Al(OH)3 was also made using Temkin--Schwarzman'smethod and by means of regression analysis. Investigations of the potential--pH diagrams of Al-H2Osystem and thermodynamic analysis of the thermal decomposition of Al(OH)3 provide a certainguide for the formation of boehmite sol and the heat treatment of boehmite powder, respectively.