Synthesis of nano-sized spinel (MgAl2O4) from short mechanochemically activated chloride precursors and its sintering behavior

MgAl2O4 is the most important compound in the MgO-Al2O3 system which can be produced through various methods. In the present work, synthesis and sintering behaviour of nano-sized spinel powder produced through mechano-chemical process were studied. For this purpose, MgCl2 center dot 6H(2)O, AlCl3 center dot 6H(2)O, and NaOH reagents altogether with a small amount of water were mixed and subjected to high-energy ball milling for a short time (similar to 10 min). After confirming the occurrence of solid-phase displacement reactions by X-ray diffraction, the as-milled powders were washed, dried and then heated from 400 degrees C to 1200 degrees C for 2 h. The heated powders were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, simultaneous thermal analysis, BET and transmission electron microscopy techniques. It was found that pure nano-sized spinel phase, with 8-12 nm mean particle size and 76.9 m(2)/g specific surface area is obtainable through heating the precursor for 2 h at 800 degrees C. The synthesized powders were sintered at 1500 degrees C and obtained 93.8% of the theoretical density. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B. V. and The Society of Powder Technology Japan. All rights reserved.