SYNTHESIS OF MGAL2O4 SPINEL - SEEDING EFFECTS ON FORMATION TEMPERATURE

Four different methods of MgAl2O4 spinel synthesis in the presence and absence of seeds were studied. The four methods used for MgAl2O4 synthesis were (a) one sol (boehmite) and one solution [Mg(NO3)2]; (b) two sols (boehmite and magnesia); (c) two nitrates (Al and Mg nitrates) and two alkoxides (Al isopropoxide and Mg ethoxide). The use of a nitrate route led to the formation of spinel at the lowest temperature without the influence of seeding. Seeding with spinel crystallites of all the powders except the one-sol and one-solution diphasic gels apparently resulted in a lower formation temperature of MgAl2O4 spinel, and this lowering of crystallization temperature can be explained by the nucleation and epitaxial growth mechanism.