Diamond deposition on carbon fibers

Diamond films have been deposited on carbon fibers with diameters as small as 5 μm by microwave plasma assisted chemical vapor deposition. An ultrasonic pretreatment of the fibers in a bath containing methanol and diamond paste was required for successful coating of the fibers. In the absence of such treatment, the fibers were completely etched within a few minutes under the plasma. Raman spectroscopy indicated good quality diamond formation with very little graphitic component. Films with thicknesses between 1 and 30 μm can be reproducibly obtained by this method.