Combustion synthesis, characterization and sintering behavior of magnesium aluminate (MgAl_2O_4) powders

摘要

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 ℃ a spinel powder with a BET surface area of 175.8 m~2 g~(-1) and an average crystallite size of 4.9 nm. Urea and triethylenetetramine fuel mixture lead after annealing at 700 ℃ to a spinel powder with an average crystallite size of 30.8 nm and BET specific surface area of 33.3 m~2 g~(-1). After sintering at 1500 ℃ 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 MgAl_2O_4.