Graphite fibers (Fortafil 6T) have been coated with chromium carbides by diffusing chromium to fibers through a solid layer of copper. Tensile strength and the elastic modulus of coated fibers were measured as a func tion of the thickness of the coating. It was found that mechanical proper ties deteriorate with increased thickness of chromium carbides. It is be lieved to be related to the pre-existing Griffith cracks and possible forma tion of new cracks in the coating during tensile tests of individual fibers.
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