Solid-state Reaction Preparation and Sintering Behavior of MgAl₂O₄ Nanopowders

Well-crystallized MgAl2O4 nanopowders were prepared by calcining a powder mixture of Al(OH)(3) and MgSO4 at 800 degrees C, and then washing with water. The effect of Mg/Al atomic ratios on the particle sizes and agglomeration degrees, and sintering behavior of MgAl2O4 nanopowders were studied by differential thermal and thermogravimetric analysis (DSC/TG), X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The obtained MgAl2O4 nanopowders have an average particle size of 12 nm, a narrow size distribution, and weak agglomeration. The formation of MgAl2O4 can be attributed to a solid-state reaction between gamma-Al2O3 and MgSO4. Besides, these MgAl2O4 nanopowders own an excellent sinterability, e.g., a relative density of 95% can be achieved after sintered at 1450 degrees C for 1 h.