Development of Spinel Magnesium Aluminate by Solution Combustion Route Using Thiourea and Urea as Fuel

In the present article spinel phase magnesium aluminate was synthesized using Magnesium nitrate, Al-nitrate precursors in 1:2 molar ratio using urea and thiourea as fuel and reducing agent. Nitrate salts were mixed in a stoichiometric ratio in distilled water with three different molar ratios of two different fuels: urea and thiourea. The temperature of crystallization was obtained after thermal analysis followed by annealing at a fixed temperature, fixed soaking period for urea as fuel while variable temperature and soaking period were required for thiourea as fuel. FTIR analyses were carried out of the samples to verify the M-O co-ordinations for the phase formation. Prominent octahedral M-O stretching was noted at about 609 cm-1 while that of Al-Mg-O stretching was noted at about 1100 cm-1 for thiourea based samples. Using Urea as fuel Al-O stretching was noted at about 539cm-1 while that of Al-Mg-O vibration was noted at about 677cm-1. Morphological features of the synthesized samples were observed by SEM. Agglomeration was noted for both urea and thiourea as fuel having irregular polygon shape. Using thiourea as fuel, a bit of porous structure was noted while for urea as fuel negligible porosity was noted.