Low temperature synthesis of a stable compound of magnesium aluminum titanate using microwave heating

摘要

The major problem associated with application of aluminum titanate is decomposition to Al_2O_3 and TiO_2 oxides during heat treatment (in the range of 900-1280°C ). In the present study, a stable compound of magnesium aluminum titanate ceramics (Mg_(0.6)Al_(0.8)Ti_(1.6)O_5) has been successfully synthesized with a straightforward non hydrolytic sol-gel process using inorganic metal compound. The raw materials were MgCl_2.2H_2O, AlCl_3, TiCl_4, and citric acid that were dissolved in ethanol. Prepared gel was dried at 120°C and calcined at various temperatures using microwave heating. The results of X-ray Diffraction (XRD) and Simultaneous Thermal Analysis (STA) demonstrate that the direct crystallization of mono-phase magnesium aluminum titanate from fluffy precursor at a temperature below aluminum titanate decomposition temperature range is feasible. The formation of crystalline Mg_(0.6)Al_(0.8)Ti_(1.6)O_5 phase starts at about 400°C. Also, Field Emission Scanning Electron Microscopy (FESEM) study and Brunauer-Emmett-Teller (BET) analysis represent the nano-metric size of the mesoporous particles. The average particle size and specific surface area of powders were lower than 20 run and more than 98 m~2g~(-1), respectively, at low temperatures.