Carbon-fiber composites fabrication techniques

These expensive carbon-carbon fiber composites are used for thermally demanding applications like aircraft and racecar brakes. Typically, both pads and rotors are made of carbon composite. These friction couples have a relatively low friction level, which is insensitive to the high temperatures experienced in operation. Friction couple components are expensive to manufacture as they are fabricated by time-consuming chemical vapor deposition techniques. Carbon-carbon systems suffer from low cold friction and are best suited for hot operation. 

Composite fabrication techniques were examined and in particular, the work of TW Thorpe on filament winding should be mentioned, basically for use with the classified centrifuge project for separation of uranium isotopes. Designing with cfrp has been covered by Pearce [112] and more specifically, designing with carbon fiber reinforced metals [113]. 

The most common matrix materials of carbon-fiber composites are the polymers, also called resins or plastics. Carbon-reinforced polymers are low-density, high-strength, and high-modulus composites with extensive applications, especially in aerospace as mentioned above. Their cost is still high but is gradually decreasing as the fabrication techniques are becoming less labor-intensive. 

The various fabrication techniques for carbon-fiber composites include filament winding, injection and compression molding, pultrusion, and wet layup. They are described in Ref. 9. 

A recent successful application of carbon/carbon composites is the tool for superplastic forging of titanium illustrated by Figure 6 tubes up to 1.5 m in length can be forged at temperatures up to 1000°C, thus offering a rapid alternative fabrication technique to present production methods, e.g., riveted tubes (15). Contact brushes for electrical commutators, made with carbon fibers and carbon/carbon composites (16), are opening another new field of application. Furthermore, pistons in diesel engines have been proposed to be made from carbon/carbon composites (17). 

Hollow fibers and spheres of zeolite (labeled as HFZ and HSZ, respectively) were successfully fabricated using carbon fibers and polystyrene (PS) spheres as templates respectively, through layer-by-layer technique, coupled with removal of the templates by calcination. The optimum performance conditions to obtain these kinds of materials were systematically studied. The wall thickness and composition of these novel materials can be readily tailored by varying the number of nanozeolite/PDDA (poly(diallyldimethyl ammonium chloride)) deposition cycles and zeolite type used, respectively. The properties of these novel materials were characterized by means of XRD, IR and SEM. 

The infiltration of carbonaceous structures by liquid silicon or silicon vapor is also an interesting technique to produce SiC components. Especially the Si-inhltration of C-structures coining from natural materials like wood offers the possibility for low cost fabrication of SiC, and has already been described in Sect. 4. Infiltration of polymer-matrix derived carbon fiber reinforced carbon is schematically drawn in Fig. 14 [255, 256]. The production of complex SiC-composite parts and components as well as big parts is possible by this route. 

A novel route to pure and composite fibers of polypyrrole was recently reported by Han and Shi [42]. An organic salt (FeAOT) was synthesized by the reaction of sodium l,4-bis(2-ethyUiexyl)sulfosuccinate (AOT) and ferric chloride. It was fabricated into nanofibers by manual drawing and electrospinning. Long PPy fibers were obtained for the first time by a vapor deposition reaction of pyrrole on the FeAOT fibers, and this technique was extended to the synthesis of PPy composite fibers with multiwalled carbon nanotubes (PPy-MWCNT fibers). The PPy and PPy-MWCNT fibers had a nanoporous morphology, a conductivity of 10-15 S cm and a tensile strength of 12—43 MPa. Studies of the electrochemistry and current-voltage characteristics of the PPy fibers were also reported. 

Electrophoretic infiltration is a novel technique for the fabrication of fiber reinforced composites used by Kooner et al [234]. The technique involves arranging the fibers as one of the electrodes such that deposition of the colloidal ceramic occurs in the fiber preform. This method was investigated for the carbon fiber reinforced Si3N4 composite system and produced green composite microstruetures with good infiltration uniformity and fiber distribution, with hardly any macro defects. 

The pressure casting technique was used by Cheng and workers [78] to fabricate carbon fiber reinforced Al composites with the hybridization of a small amount of particulates or... 

The fabrication of Cu or Ni coated carbon fiber reinforced Al using a centrifugal pressure infiltration method has been described by a member of NIKKEI Techno-Research [88]. The centrifugal casting technique appears to be an innovative method of fabricating composite materials. 

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