Ceramics-Silikáty 49 (4) 259-262 (2005)

LIQUID PHASE SINTERING OF SiC WITH RARE-EARTH OXIDES

M. Balog, K. Sedláčková, P. Zifčák, J. Janega

A variety of sintering additives Y₂O₃/Yb₂O₃/Sm₂O₃ together with AlN have been used for liquid phase sintering of silicon carbide. The hot pressed samples were further annealed to emphasize the effect of sintering additives on microstructural development. Remarkable influence of sintering additives on the microstructure was observed. Dependences of mechanical properties on microstructure and grain boundary chemistry were evaluated in more details. The hardness of SiC ceramics increased with decreasing ionic radius of the rare-earth elements, and contrary, the fracture toughness decreased.

Keywords: SiC, Liquid phase sintering, Microstructural development, Hardness, Fracture toughness