Study on the Highe-Temperature Mechanical of Al<sub>2</sub>O<sub>3f</sub>/SiO<sub>2</sub> and SiO<sub>2f</sub>/SiO<sub>2</sub> Ceramic Matrix Composites

Al 2 O 3f /SiO 2 and SiO 2f /SiO 2 ceramic matrix composites were manufactured by silica sol-infiltration-sintering method. The mechanical properties of composites under room temperature to 1200 °C were tested on-line with universal testing machine. It is found that Al 2 O 3f /SiO 2 composites present a higher strength than SiO 2f /SiO 2 at room temperature and 1000 °C. The strength of two composites dramatic decrease with temperature increased to 1200 °C. Also, SEM and XRD methods were adopted to investigate the micro-structure of cross-fraction and crystal phase of composites, indicating a strong interaction between fibers and matrix under high temperature. Finally, the dielectric properties of two composites under room temperature to 1200 °C were discussed.