Solidus, Subsolidus, and Subdissociation Phase Equilibria in the System Fe‐Al‐O

The objective of this investigation was to determine phase relations in the system Fe‐Al‐O outside the composition and temperature regions of oxygen dissociation. Subsolidus phase equilibria were studied using inert atmospheres and the quenching technique. Compatibility relations are presented on isothermal sections at 1000°, 1250°, and 1350°C. Lattice parameters of iron‐bearing spinel, Al 2 O 3 and Fe 2 O 3 are given as a function of composition. Stability and some structural relations of the compound Fe 2 O 3 Al 2 O 3 are discussed. Solidus surfaces in the nondissociating portions of the system have been established using both published data and measurements made during this investigation.