Fiber-reinforced composites with polymer-derived matrix: processing, matrix formation and properties

Carbon and SiC fiber-reinforced ceramic matrix composites were prepared via infiltration of fiber preforms using the polymer infiltration technique an d polymer pyrolysis. Suitable silazane (SiCN) precursors with appropriate t hermosetting behavior, viscosity and ceramic yield were synthesized, starti ng from functionalized chlorosilanes. Microstructural development and fract ure behavior was studied after various infiltration and pyrolysis cycles. R esidual stresses induced during processing were evaluated. Mechanical and t hermo-physical properties of the composites with polymer-derived matrix, i. e. 3-pt bending strength and thermal expansion coefficients (CTE), were mea sured dependent on reinfiltration cycles and fiber orientation. The oxidati on resistance was investigated. Specific pyrolyzed samples were infiltrated via silicon melts in order to enhance corrosion and wear resistance. (C) 1 999 Elsevier Science Ltd. All rights reserved.