Chemical vapour composite

During CVC processing, a CH3SiCl3 precursor is bubbled and delivered by the H2 carrier gas. Then the reactant gases and reinforcements are mixed together and injected onto the graphite substrate, which is heated at a preset temperature. Like a CVD process, a CVC process can essentially produce a uniform layer of deposit onto the surface of the substrate. Hence, it allows the geometry of the base 

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Chemical vapour deposition (CVD) is employed to prepare adherent films of controlled composition and thickness. Protective coatings, micro- and opto-electronics, ceramic fibres and ceramic-matrix composites production represent the usual applications of this technique, which allows surfaces of complex geometry to be uniformly coated. 

Growth of crystals from vapour may be divided into two categories depending on whether the change, vapour—> crystal, is physical or chemical. When the composition of the vapour and the crystal is the same, the process is physical examples are sublimation-condensation and sputtering. The process is termed chemical when a chemical reaction occurs during the growth in such a case, the composition of the solid is different from the vapour. The use of chemical vapour deposition (CVD) as a... 

Various researchers have used different techniques for the fabrication of ceramic matrix composite (CMC) by using (a) chemical vapour deposition (CVD), (b) chemical vapour infiltration (CVI) and (c) modelling of CVI [43-54], but it is difficult to fabricate glass/glass-ceramic composite using these techniques. 

There is also scope for the development of new techniques such as chemical vapour infiltration (CVI) (Caputo and Lackey, 1984 Caputo et al., 1985), normal chemical reaction bonding processes, laminar sialon composites, etc. More recently, laminated composites in non-oxide and sialons have demonstrated very promising results for strengthening (Goto and Kato, 1998) and even achieved a non-brittle failure behaviour accompanied by high damage tolerance (Yu and Krstic, 2003 Yu et al., 2005). 

Caputo, A.J. and Lackey, W.J., (1984), Fabrication of fibre-reinforced ceramic composites by chemical vapour infiltration , Ceram. Eng. Sci. Proc., 5(7-8), 654—667. 

The increasing use of light ceramic composites for high temperature and space applications has stimulated the development and optimization of the Chemical Vapour Infiltration technique. The use of conventional ceramic techniques for the fabrication of fibre-reinforced composites damages the fibres both mechanically as chemically. Also, the high process temperature causes a thermal degradation of the fibres. 

One major issue of the nanotube elaboration processes is to produce nanotubes with controlled dimensions (diameter, length) and without byproducts (catalytic residues, other carbonaceous particles). This is nearly achieved with processes such as catalytic chemical vapour decomposition using supported catalysts. However, the arc discharge method remains the most common one and is perhaps the easiest way to produce the large quantities of nanotubes required for the elaboration of composites (49). The dimensions of... 

High-performance Ceramic Matrix Composites and Chemical Vapour Infiltration... 

Chemical vapour infiltration (CVI) is an extension of CVD processes only when a CVD process occurs on an internal surface of a porous substrate (especially for the fibre preform). As compared with CVD, the CVI process for ceramics is much more effective and important because it is the optimal technique to fabricate fibre reinforced ceramics and particularly carbon fibre reinforced carbon and advanced ceramic matrix composites. Both CVI and CVD techniques share some common features in overall chemistry, however, the CVI is much more complex than the CVD process in mass transport and chemical reactions. 

Some representative papers on chemical vapour deposition, ceramic and ceramic matrix composites and related area are listed here ... 

Review, status, and future of the chemical vapour infiltration process for fabrication of fibre-reinforced ceramic composites, Lackey, 1989 [138]... 

Fabrication of fibre-reinforced ceramic composites by chemical vapour infiltration, Lackey and Starr, 1990 [140]... 

Lackey WJ, Starr TL (1990) Fabrication of fibre-reinforced ceramic composites by chemical vapour infiltration processing, structure and properties. In Mazdiyasni K S (ed) Fibre reinforced ceramics. Noyes, Park Ridge, NJ, pp397 150... 

Huttinger KJ (2003) Foundamentals of chemical vapour deposition in hot wall reactors. In Dlhaes P (ed) Fibres and composites. Taylor Francis, London, pp75-86... 

Stinton DP, Lackey WJ (1985) Simultaneous chemical vapour deposition of SiC-dispered phase composites. Ceram Eng Sci Proc 6 707-713... 

Characteristics of Forced-Flow-Chemical Vapour Infiltration Composites... 

Christin F, Naslain R, Bernard C (1979) A thermodynamic and experimental approach of silicon carbide CVD. Application to the CVD-infiltration of porous carbon composites. In Sedgwick TO, Lydtin H (eds) Proceedings of the 7th international conference on chemical vapour deposition. Electrochemical Society, Pennington, NJ, pp499-514... 

Marinkovic S, Dimitrijevic S (1985) Carbon/carbon composites prepared by chemical vapour deposition. Carbon 23 691-699... 

Brennan JJ (1990) Interfacial studies of chemical-vapour-infiltrated ceramic matrix composites. Mater Sci Eng A126 203-223... 

Stinton DP, Lowden RA, Besmann TM (1992) Fibre-reinforced tubular composites by chemical vapour infiltration. In Besmann TM, Gallois BM, Warren JW (eds) Chemical vapour deposition of refractory metals and ceramics II. Materials Research Society, Pittsburgh, PA, pp233-238... 

Vaidyaraman S, Lackey WJ, Freeman GB, Agrawal PK, Langman MD (1995) Fabrication of carbon-carbon composites by forced flow-thermal gradient chemical vapour infiltration. J Mater Res 10 1469-1477... 

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