Mechanical properties of SiC ceramics sintered with RE2O3 (RE: Sc, Lu, Y) and AlN Additives

Abstract

Highly densified Silicon Carbide (SiC) ceramics with 10 vol.% sintering additives, RE2O3 (RE: Sc, Lu, Y) and AlN, were prepared via hot pressing in N2 atmosphere. The influence of sintering additive composition on the mechanical properties of the sintered specimens is discussed. The Sc2O3-AlN system consisted of equi-axed grain structure, while the Lu2O3-AlN and Y2O3-AlN systems rendered largely grown platelet grains. While fracture toughness was enhanced with regards to the contribution of crack deflection and crack bridging mechanisms for intergranular fracture, strength remained almost the same for all specimens.