Abstract
Fine powders of a-Al2O3 were prepared by hydrothermal oxidation of Al metal powders. Under 100 MPa, Al yielded Boehmite between 200°C and 400°C, and finally produced a-A1203 above 600°C in the open capsule. On the other hand, unreacted Al metal remained until 700°C in the sealed capsule. This hydrothermal oxidation method is one of the methods to prepare fine a-Al2O3 particle having around I Inn in size.
