Patent ID: 7309609

Claim:
A method of detection of oxidation of carbon-containing fibers or fiber-bundles in composites which are fiber-reinforced C/SiC materials in which carbon fibers or graphite fibers are present in a ceramic matrix comprising predominantly SiC and Si, using the eddy current method, wherein the said composites consist of carbon or graphite fibers or fiber bundles and a non-conducting or semi-conducting ceramic matrix, and wherein the said fibers or fiber bundles are electrically conducting short fibers isolated by the said non-conducting or semiconducting ceramic matrix such that the fibers or fiber bundles are effectively electrically insulated and there is no skin effect upon electrical induction, comprising applying an alternating magnetic field to the composite, the eddy current generated within the fibers causing a signal which is markedly different for oxidated fibers and non-oxidated fibers.