ABSTRACT
Fiber coatings can have an important influence on the debond strength and frictional stress in a ceramic matrix composite. A coating providing an appropriately weak interface results in a tough composite, with fiber pullout evident at fracture surfaces (Figure 1). An early indication of the presence of a variable carbon-rich layer in Nicalon fiber reinforced silicon carbide was outlined earlier, and many more investigations into fiber coatings have been conducted. These have involved both coatings formed in situ and coatings deposited on fibers prior to composite fabrication. In addition to influencing interfacial properties, coatings have the possibility of retarding fiber-matrix reactions and retarding fiber oxidation.
