Weakly agglomerated α-Al2O3 nanopowders prepared by a novel spray precipitation method

In this paper, weakly agglomerated and well dispersed α-Al2O3 powders were synthesized by a novel spray precipitation method. It was demonstrated that the as-prepared powders exhibited better dispersity than powders from conventional precipitation due to the increased phase contact and reaction area during the precipitation process. The effects of different titration ways, calcination temperature and holding time on the morphology, phase composition and sintering behaviour of Al2O3 powders were systematically investigated. Weakly agglomerated and well crystallized α-Al2O3 powders were obtained when the as-prepared precursors were calcined at 1150 °C for 2 h in air. The average particle size of α-Al2O3 powders with higher sintering activity was approximately 68.6 nm, and the specific surface area was above 22.4 m2 g−1.