Abstract: MgAl₂O₄ spinel nanometer powders were synthesized via sol-gel process of aluminium
isopropoxide that hydrated in the solution of magnesium nitrate with tetrahydrofuran being stabilizer. The crystallization process of
MgAl₂O₄ precursor and the effect of calcination temperatures on spinel grain size and sinterability were investigated by DTA, XRD and
TEM. The results indicated that this method could lower the formation temperature of MgAl₂O₄ apparently. Monolithic spinel nanometer
powders were produced at the temperature as low as 900℃, with primary particle sizes of about twenty nanometers. The powder
calcined at 900℃ showd best sinterability, and dense spinel ceramic with 99% relative density could be obtained at the sintering
temperature as low as 1600℃.

Key words: semi-alkoxide sol-gel method, Mg-Al spinel, nanometer powder