Synthesis of Magnesium Aluminate Spinel Platelets from α-Alumina Platelet and Magnesium Sulfate Precursors

Abstract

Spinel platelets were formed from a powder mixture of 3-5 μm wide and 0.2-0.5 μm thick α-Al2O3 and 1-8 μm (average 3 μm MgSO4 heated 2 h at 1200°C. The hexagonal platelet shape of the original α-Al2O3 platelet was maintained in the spinel, although their size was slightly increased and their surface roughened. When a mixture of α-Al2O3 platelets and MgO powder was heated 3 h at 1400°C, the spinel formed lost the platelet morphology of the alumina.