Properties of Al2O3-SiCw Composites Fabricated by Three Preparation Methods

$Al_2O_3$-SiC composites reinforced with SiC whisker ($SiC_w$) were fabricated using three different methods. In the first, $Al_2O_3-SiC_w$ starting materials were used. In the second, $Al_2O_3-SiC_w$-SiC particles ($SiC_p$) were used, which was intended to enhance the mechanical properties by $SiC_p$ reinforcement. In the third method, reaction-sintering was used with mullite-Al-C-$SiC_w$ starting materials. After hot-pressing at $1750^{\circ}C$ and 30 MPa for 1 h, the composites fabricated using $Al_2O_3-SiC_w$ and $Al_2O_3-SiC_w-SiC_p$ showed strong mechanical properties, by which the effects of reinforcement by $SiC_w$ and $SiC_p$ were confirmed. On the other hand, the mechanical properties of the composite fabricated by reaction-sintering were found to be inferior to those of the other $Al_2O_3$-SiC composites owing to its relatively lower density and the presence of ${\gamma}-Al_2O_3$ and ${\gamma}-Al_{2.67}O_4$. The greatest hardness and $K_{1C}$ were 20.37 GPa for the composite fabricated using $Al_2O_3-SiC_w$, and $4.9MPa{\cdot}m^{1/2}$ using $Al_2O_3-SiC_w-SiC_p$, respectively, which were much improved over those from the monolithic $Al_2O_3$.

제조방법에 따른 Al2O3-SiCw 복합체의 특성