Low Temperature Synthesis of Hexagonal Shaped α-Al2O3 Using a Solvothermal Method

This study demonstrates the low temperature synthesis of α-Al2O3 by solvothermal method using gibbsite alumina precursor in 1, 4-butanediol solvent according to various pH conditions. In acidic solution, an orthorhombic boehmite (AlOOH) structure was obtained after solvothermal reaction. A significant result in this study was that the solvothermally synthesized alumina in pH=9 at 300 °C for 36 h represented a rhombohedral α-Al2O3 structure hexagonal shaped with about 1.5~2.0 μm of particle size. Otherwise, the α-Al2O3 structure was rather changed to the mixture of a boehmite and α-Al2O3 structures above pH=11. In the case of α-Al2O3 synthesized at pH=9, the specific surface area was 26.18 m2/g, and the particles that were stable in acidic solution resulted in 61.80 mV of zeta potential.