Template formation of magnesium aluminate spinel microplatelets in molten salt

摘要

Magnesium aluminate, MgAl_2O_4 (MA), microplatelets were synthesized using a molten salt technique. alpha-Alumina platelets partially decomposed from aluminium sulphate were reacted with either commercial magnesium oxide or magnesium nitrate in the molar ratio 1:1 to synthesize spinel platelets. Molten salts such as chloride, MC1 (M velence Li, Na, and K) and potassium sulphate were used for MA synthesis and the salt to oxide ratio was kept at 3:1 for all compositions. Reactants and molten salt mixes were fired in an alumina crucible for 3 h at from 800 to 1150 deg C. XRD revealed complete MA without formation of any secondary phase for powders fired for 3 h at 1100 deg C. Electron microscopy revealed the MA platelet morphology and size was the same as the alpha-alumina platelets indicating a 'template process' during molten salt synthesis.