Stress in Coated Fibers

Ikble 6.2. Physical and mechanical properties of fibers and coatings. 

Run Temperature [°C] Hz Flow [l/min] MTS Flow [g/min] [Pa/Torr] Tensile Strength average [GPa] range Weight for 15.2 cm fiber [g] Coat- ing Thick- ness [pm] Fiber Agglo- mera- tion [%] 

Deposition experiments were performed on Amoco T-300 unsized carbon fibers (3000 filaments/tow) using the hot wall continuous fiber coating furnace previously described. For all the experiments, methyltrichlorosilane (MTS = CHsSiClj) was 

The box statistical study was designed and completed to find the optimal conditions for SiC deposition. The temperature was varied from 1050 to 1400°C, H2 flow rate was varied from 1.5 to 3.5 L/min, and MTS flow rate was varied from 0.15 to 1.35 L/min. The pressure inside the furnace and the fiber speed were kept constant at 13.3 kPa and 10 cm/min, respectively. During each experiment, a fiber vibration device was used which cyclically applied and released tension, at one second intervals, along the axis of the fiber tow in an attempt to spread the tow and to minimize agglomeration of the individual filaments within the tow. 

Hitachi S4100 and Cambridge 150 scanning electron microscopes were used to characterize the coated fibers at magnifications of 200 to 7000 x. Micrographs taken at 

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Fibers that retain their high strength to temperatures in the range 1200-1500°C are needed for use as the reinforcement in ceramic and metal matrix composites. This portion of this chapter deals with the fabrication of SiC fibers using CVD. It is divided into sections on current status, hot- and cold-wall reactor designs, stresses in coated fibers, processing results, and economics. 

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