THERMAL-BEHAVIOR OF POLYMER-DERIVED CERAMICS .4. SI-C-N-O FIBERS FROM AN OXYGEN-CURED POLYCARBOSILAZANE

Fibered Si-C-N-O-based ceramics from a polycarbosilazane precursor (copolymer) are studied, then compared to other ceramic materials previously prepared and described in other papers. The emphasis is upon the structural and textural features as observed by high-resolution transmission electron microscopy and their evolution with an increasing heat-treatment temperature up to 1600-degrees-C. Both argon or nitrogen atmospheres were used. Specifically, the peculiar behavior of the material during the amorphous to crystalline transition until degradation is revealed. The consequences on the nucleation and the growth of the SiC grains, and the electrical and mechanical properties are discussed.