Characteristics of Duplex Ln α β Sialon in Mechanical Properties and Thermal Stability

The phase control, mechanical properties and microstructures of α β Sialon ceramics were compared among the three counterpart Dy , Sm and (Dy+Sm) α β Sialon compositions The results show that the dulpex Ln α β Sialon possesses advantage over the single Ln α β Sialon Unlike Sm Sialon, in the (Dy+Sm) Sialon compositions melilite phase does not occurs during the formation of α Sialon Therefore, the phase compositions based on phase equilibrium can be easily controlled Sm Sialons have a rather finer microstructure, higher flexural strength and fracture toughness These characteristics can remain in (Dy+Sm) Sialon ceramics Dy Sialons possess a higher hardness and Dy α′ is much stable than Sm β′ during heat treatment, which can also remain in (Dy+Sm) Sialon ceramics Therefore, (Dy+Sm) α β Sialon ceramics are quite stable during heat treatment and possesses good mechanical properties