Effect of fiber coatings on interfacial shear strength and the mechanical behavior of ceramic composites.

摘要

Thin coatings (boron nitride and carbon) deposited on ceramic fibers prior to densification employing chemical vapor infiltration techniques have been used to limit fiber-matrix bonding. This has resulted in improvements in strength and toughness at room and elevated temperatures in Nicalon(reg sign) fiber-reinforced/SiC matrix composites. The properties of the fiber-matrix interface in fiber-reinforced ceramic composites have been examined utilizing an indentation method in which a standard microhardness indentor is used to push on fibers embedded in the ceramic matrix. Compositions and microstructures at the interface have been characterized employing analytical electron microscopy. Correlations between interfacial phenomena and observed mechanical behavior have been made. 16 refs., 5 figs., 1 tab.