Synthesis and Characterization of MgAl ₂ O ₄ Spinel Precursor from a Heterogeneous Alkoxide Solution Containing Fine MgO Powder

Abstract

A precursor was synthesized from a heterogeneous alkoxide solution that contained fine MgO powder, which allowed the preparation of MgAl 2 O 4 spinel powder with high sinterability characteristics. The precursor consisted of a mixture of boehmite (AlO(OH)) and a mixed hydroxide (Mg 4 Al 2 (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 γ‐Al 2 O 3 at higher temperatures. Dense polycrystalline spinel could be obtained from the calcined powders at sintering temperatures as low as 1400°C.