Abstract
In attempt to synthesize β-Al2O3 platelets using a novel method, powder mixtures consisting of γ-Al2O3 and NaF were heated in a platinum crucible. The effect of the mixing ratio of the raw materials, heating temperature and duration of heating at the selected temperature on the formation of the β-Al2O3 platelets was investigated. When powder mixtures consisting of γ-Al2O3:NaF=1:X (X=1-4; molar ratio) were heated at 900°C for 3h, β-Al2O3 hexagonal platelets formed. The size of the platelets were 3-8μm in diameter and 10-20 in aspect ratio, independent of the amount of NaF in the starting powders. When a powder mixture consisting of γ-Al2O3:NaF=1:2 was heated at 700 to 1100°C for 3h, β-Al2O3 platelets systematically formed. The size and morphology of the platelets were the same as above, independent of heating temperature. In addition, when the powder mixture consisting of γ-Al2O3:NaF=1:2 was heated at 800°C for 0h, β-Al2O3 platelets with the same size and morphology formed.
