PROCESSING, STRUCTURE, AND PROPERTIES OF MULLITE FIBER MULLITE MATRIXCOMPOSITES

Oxide fiber/oxide matrix composites form an important and very attract ive subpart of ceramic matrix composites because of their inherent sta bility in oxidizing atmospheres at high temperature. In particular, mu llite fiber/mullite matrix composites have the potential of high tempe rature usage in oxidizing atmospheres. The interface in mullite fiber/ mullite matrix was engineered by using thick BN (1 mu m) or BN/SiC dou ble coating on mullite fibers, such that deformation mechanisms conduc ive to toughness enhancement could be brought to play. Significant imp rovements in the room temperature mechanical properties of these mulli te fiber/mullite matrix composites could be achieved by incorporation of these interfacial coatings and by using a colloidal processing rout e to make dense mullite matrix.