Synthesis and characterization of MgAl2O4 spinel precursor from a heterogeneous alkoxide solution containing fine MgO powder

A precursor was synthesized from a heterogeneous alkoxide solution that con tained fine MgO powder, which allowed the preparation of MgAl2O4 spinel pow der with high sinterability characteristics. The precursor consisted of a m ixture of boehmite (AlO(OH)) and a mixed hydroxide (Mg4Al2(OH)(14). 3H(2)O) . The spinel phase formed through two steps: (i) decomposition of the mixed hydroxide at low temperature and (ii) solid-state reaction between MgO and gamma-Al2O3 at higher temperatures. Dense polycrystalline spinel could be obtained from the calcined powders at sintering temperatures as low as 1400 degrees C.