Carbon fiber composites processing

For rayon fiber based composites (Sections 3 and 4) the fiber and powdered resins were mixed in a water slurry in approximately equal parts by mass. The isotropic pitch carbon fiber composites (Section 5) were manufactured with less binder, typically a 4 1 mass ratio of fiber to binder being utilized. The slurry was transferred to a molding tank and the water drawn through a porous screen under vacuum. In previous studies [2] it was established that a head of water must be maintained over the mold screen in order to prevent the formation of large voids, and thus to assure uniform properties. The fabrication process allows the manufacture of slab or tubular forms. In the latter case, the cylinders were molded over a perforated tubular mandrel covered with a fine mesh or screen. Moreover, it is possible to mold contoured plates, and tubes, to near net shape via this synthesis route. 

The combination of toxic hazard and high price (itself in part due to the extra measures needed in production processes to ensure the workers safety) has been an effective brake on commercial development of beryllium chemistry. Where possible substitute, albeit less effective, materials are often used titanium as an alternate lightweight metal or carbon fiber composites, phosphor-bronzes in place of beryllium alloys, aluminum nitride in place of BeO (1). 

An obvious solution to the surface area limitation is to distribute the selected metal over a high surface area support. However, as metal is consumed in the process, a conventional metal support system would require frequent replacement. A more attractive proposition is offered by the availability of permeable monolithic carbon fiber composites, which were discussed earlier in this chapter. The ability to make these composites electrically conducting allows metals to be... 

Next to mechanical properties, the most important characteristics of a carbon-carbon composite(C/C) are thermal conduction and thermal expansion. In this paper, several investigations have been made into carbon fiber arrangement relationships for different carbon-carbon composite materials. Pitch-derived carbon matrix-carbon fiber composites have been used, processed by means of the hot isostatic pressing (HIP) technique for converting pitch into a dry carbon fiber preform. Repeated HIP cycles are required to build the composite matrix up to an acceptably high density/low porosity for deployment in severely ablative environments. 

Iroh, J.O., and C. Williams. 1999. Formation of thermally stable polypyrrole-naphthalene/benzene sulfonate-carbon fiber composites by an electrochemical process. Synth Met 99 1... 

Table 4.9 gives the composition of various oils and pitches. The materials richest in asphaltene are the most suitable for conversion to carbon fibers. Manufacturing processes for pitch based carbon fibers are shown in Figure 4.21. 

Colton J, Leach D, Processing parameters for filament winding thick-section PEEK carbon-fiber composites. Polymer Composites, 13(6), 427 34, 1992. 

Galvanic corrosion may occur in carbon fiber composites if aluminum fasteners are used, due to the chemical reaction of the aluminum with the carbon. Coating the fastener guards may prevent corrosion but adds cost and time to the assembly process. As a result, aluminum fasteners are often replaced by more expensive titanium and stainless steel fasteners in carbon fiber composite joints. 

D.D.L. Chung, Chapter 2 — processing of carbon fibers, in D.D.L. Chung (Ed.), Carbon Fiber Composites, Butterworth-Heinemann, Boston, 1994, pp. 13—53. 

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