The System MgO–MgAl 2 O 4

In the determination of the liquidus, solidus, and subsolidus of the system MgO‐MgAl 2 O 4 the limits of the solid solution of A1 ions in periclase and Mg ions in spinel were measured. By using both X‐ray diffraction and optical techniques, the maximum periclase solid solution was found at 82 wt% MgO, 18 wt% A12O3 (9.5% A1 3+ ) and maximum spinel solid solution at 39% MgO, 61 % A1203 (6% Mg ++ ). Periclase and spinel solid solutions existed stably in easily detectable amounts at temperatures above approximately 1500°C.