Abstract: Nanometer NH₄Al(OH)₂CO₃ precursor was synthesized from NH₄Al(SO₄)₂ and NH₄HCO₃. The effect of α-Al₂O₃ seeds (-150nm) on the phase transformation and micrograph of alumina was studied. The results show that under the conditions of adding a small quantity of α-Al₂O₃ seeds, the nucleating temperature can be lowered, the transition rate enhanced effectivelly, the transition of Al₂O₃ from θ to α phase can be completed at a lower temperature, and the grain accumulation can also be influnced to a certain extent.

Key words: α-Al₂O₃, seeds, phase transformation, micrograph