Subsolidus Phase Relationships in Si 3 N 4 –AlN–Rare‐Earth Oxide Systems

The subsolidus phase relationships in Si 3 N 4 –AlN–rare‐earth oxide (Me 2 O 3 where Me=Nd, Sm, Gd, Dy, Er, and Yb) systems were studied. Solid‐solution regions with the α‐Si 3 N 4 structure were delineated along the Si 3 N 4 –“Me 2 O 3 :9AIN” joins for all of the rare‐earth oxide systems studied. The solubility limits of these solid solutions increased with decreasing size of the rare‐earth ions.