Carbon/carbon composites derived from phenolic resin/silica hybrid ceramers - Part I - Oxidation resistance and morphological properties

A novel phenolic resin/silica hybrid ceramer fabricated via the sol-gel met hod was prepared. Hybrid systems with different inorganic contents were use d as the matrix precursors to fabricate the silica containing carbon/carbon composites. Isothermal oxidation tests at temperatures ranging between 650 degreesC and 750 degreesC were employed to investigate how the oxidation r esistance of the derived carbon/carbon composites is improved. Furthermore, the isothermal oxidation test results between 550 degreesC and 615 degrees C were used to calculate the activation energy of oxidation. Experimental r esults demonstrate that the silica containing carbon/carbon composites have a better oxidation resistance than those derived from pure phenolic resins . Meanwhile, morphological observations indicate that the oxidation of carb on fibers is retarded in the phenolic resin/silica hybrid derived carbon/ca rbon composites. (C) 2001 Kluwer Academic Publishers.