Combustion synthesis of fine-particle metal aluminates

Fine-particle metal aluminates,$MAl_20_4$ where $M = Mg$, $Ca$, $Sr$, $Ba$, $Mn$, $Co$, $Ni$, $Cu$ and $Zn$ as well as $3CaO . Al_2O_3$ $(C_3A)$, $CaAl_{12}O_{19}$ $(CA_6)$ and $MgCeAl_{11}O_{19}$ have been prepared by the combustion of mixtures of the respective metal nitrates (oxidizers) and urea or carbohydrazide (fuels) at 500 or $350^0c$ respectively, over a time of 5min. The solid combustion products were identified by their characteristic X-ray powder diffraction patterns. The fine-particle nature of these metal aluminates was investigated using SEM, TEM, particle size analysis and surface area measurements. The surface areas of the as-prepared metal aluminates using carbohydrazide fuel were higher (45 to 85 $m^2g^{-1}$) compared with urea (1 to 20 $m^2g^{-1}$)