Preparation of Mullite Fiber Reinforced Mullite Composites

Abstract

In this paper, mullite fiber reinforced mullite composites were prepared by stitched structural perform, the silica sol and alumina sol. In order to improve the compatibility of mullite fiber and silica sol matrix, interface coating was made by infiltration. The composites were prepared by the method of liquid phase infiltration, and the suitable ceramic heat treatment temperature was 750∼900°C though testing the damage of fiber strength after heat -treatment at different temperatures. Results showed that SiO2-Al2O3-ZrO2 interface coating could uniformly distribute on the surface of mullite fibers, and the appropriate interfacial bonding strength was obtained, which made a contribution to the high density mullite fiber reinforced mullite composite, whose density reached 1.75∼1.8g/cm3, tensile strength, bending strength and compressive strength reached 48.7MPa,65.4MPa and 82.7MPa, respectively. Dielectric constant was 3.2±0.1, Loss angle tangent was less than8×10-3.So mullite fiber reinforced mullite composites became a new generation of high temperature wave- transparent material.