Aluminium Semi-Alkoxide Sol-Gel Synthesis and Sintering Behavior of MgAl_2O_4 Spinel Powder

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℃.