Formation of Microcrystalline α-Alumina by Glycothermal Treatment of Gibbsite

Microcrystalline α-aluminas (hexagonal plates, ∼0.1 μm wide and ∼0.025 μm thick) were prepared by treating fineparticle gibbsite in glycol at 300°C under the spontaneous vapor pressure of glycol (glycothermal treatment). The α-alumina was formed by the collapse of the glycol derivative of boehmite.