Combustion synthesis, characterization and sintering behavior of magnesium aluminate (MgAl2O4) powders

Nanocrystalline magnesium aluminate powders with different specific surface area, morphology and crystallite size were obtained by combustion synthesis using triethylenetetramine and a mixture of urea and triethylenetetramine, respectively. Triethylenetetramine yields after annealing at 700 °C a spinel powder with a BET surface area of 175.8 m2 g−1 and an average crystallite size of 4.9 nm. Urea and triethylenetetramine fuel mixture lead after annealing at 700 °C to a spinel powder with an average crystallite size of 30.8 nm and BET specific surface area of 33.3 m2 g−1. After sintering at 1500 °C for 4 h the pellets prepared from the powder obtained using triethylenetetramine reached the highest densification degree, which is 89.1% of the theoretical density of MgAl2O4.