The use of carbon-carbon composites in high temperature applications has been limited by its inherent problem of susceptibility to oxidation. A lot of research has been done in developing oxidation resistant coatings, and as a result has brought about the concept of functionally graded materials (FGMs). FGMs are often utilized as thin film coatings instead of bulk-FGMs due to difficulty in controlling the gradient. A bulk carbon-fibre-reinforced carbon-carbon/fused silica FGM has been developed for the first time. EDS tests have proven that a silicon gradient does exist across the cross section of the FGM. XRD results have also revealed no devitrification in the fused silica. The SEM images taken of the fibre-matrix interface has shown the carbon matrix component to be fully dense, although the extent of the fibre-matrix adherence is weak. More tests have yet to be done to determine the mechanical properties of the FGM.
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