Effect of Additive Composition on Mechanical Properties of Silicon Carbide Sintered with Aluminum Nitride and Erbium Oxide |
Sung-Hee Lee, Young-Wook Kim |
Department of Materials Science and Engineering, The University of Seoul |
|
|
|
ABSTRACT |
The effect of additive composition, using AlN and $Er_{2}O_{3}$ as sintering additives, on the mechanical properties of liquid-phase-sintered, and subsequently annealed SiC ceramics was investigated. The microstructures developed were quantitatively analyzed by image analysis. The average thickness of SiC grains increased with increasing the $Er_{2}O_{3}/(AlN + Er_{2}O_{3})$ ratio in the additives whereas the aspect ratio decreased with increasing the ratio. The mechanical properties versus $Er_{2}O_{3}/(AlN + Er_{2}O_{3})$ ratio curve had a maximum; i.e., there was a small composition range at which optimum mechanical properties were realized. The best results were obtained when the ratio ranged from 0.4 to 0.6. The flexural strength and fracture toughness of the SiC ceramics were $550~650;MPa$ and $5.5~6.5$ MPa${cdot}m^{1/2}$, respectively. |
Key words:
Silicon carbide, Mechanical properties, Aluminum nitride |
|
|
|