Carbide ceramic matrix composite

Baldoni, J.G., Buljan, S.T. and Sarin, V.K. Particulate titanium carbide-ceramic matrix composites , Proc. 2nd Int. Conf. Science of Hard Materials, Inst. Phys. Conf. Ser. 75, IoP/Adam Hilger, Bristol, UK, 1986. 

TABLE 5.9 Properties of Enhanced Silicon Carbide Fiber-Reinforced Silicon Carbide Ceramic Matrix Composites Source Allied SignaQ... 

Carbon-doped silicon carbide, 22 535 Carbon electrodes, 12 305, 752-758 furnaces using, 12 753 grades of, 72 754 in open-arc furnaces, 72 301 production of, 72 755 properties of, 72 755-756 Carbon elimination, in steelmaking, 23 258 Carbon fiber, 77 214-215 Carbon fiber ceramic-matrix composites, 26 773... 

Whipple s rules, 20 138 Whisker reinforcement, 5 554, 555, 654 performance in ceramic—matrix composites, 5 572-575 physical properties, 5 557t synthesis, 5 642-643 and toughening, 5 622 Whiskers, silicon carbide, 22 533-534 White... 

As noted earlier, CVl is nsed primarily to form ceramic-fiber-reinforced ceramic matrix composites. The most common of these combinations is SiC fiber/SiC matrix composites. One commercially available product has a two-dimensional 0/90 layup of plain weave fabric and fiber volume fraction of about 40%. This same composite can be fabricated with unidirectional fibers and with 45° architectures. The most commonly used SiC fiber for the preforms is Nicalon , the mechanical properties for which were provided earlier in Section 5.4.2.7. A number of other carbide and nitride fibers are also available, including Si3N4, BN, and TiC. Preform geometries can be tailored to the application in order to maximize strength and toughness in the direction of maximnm stresses. The reactions used to form the matrix are similar to those used in CVD processes (cf. Section 7.2.4) and those described previously in Eq. (3.105). 

Although few applications have so far been found for ceramic matrix composites, they have shown considerable promise for certain military applications, especially in the manufacture of armor for personnel protection and military vehicles. Historically, monolithic ("pure") ceramics such as aluminum oxide (Al203), boron carbide (B4C), silicon carbide (SiC), tungsten carbide (WC), and titanium diboride (TiB2) have been used as basic components of armor systems. Research has now shown that embedding some type of reinforcement, such as silicon boride (SiBg) or silicon carbide (SiC), can improve the mechanical properties of any of these ceramics. 

Brennan, JJ. and Prewo, K.M., Silicon carbide reinforced glass-ceramic matrix composites exhibiting high strength and toughness, J. Mat. Sci., 17, 2371-2783 (1982). 

Less-conventional processing techniques are also used to make ceramic matrix composites. Siliconized silicon carbide, for example, is made by liquid infiltration.16,17 A compact of SiC particles is formed and then presintered, or reaction bonded. Liquid silicon is then infiltrated into the structure. Many different microstructures of siliconized silicon carbide can be made in this manner. The volume fraction of SiC particles can be as high as 90vol.%. Bimodal structures have also been made by this technique. These materials are used for radiant heaters and heat exchangers.17,19... 

A typical tensile creep curve for a particulate reinforced ceramic matrix composite, siliconized silicon carbide (Si/SiC),28 is shown in Fig. 4.1. In comparison to the behavior of metals and metallic alloys, tertiary creep is suppressed in this material. There is only a slight upward curvature of the creep curve prior to failure. In many other ceramic matrix composites, tertiary... 

K. M. Prewo and J. J. Brennan, Silicon Carbide Fiber Reinforced Glass-Ceramic Matrix Composites Exhibiting High Strength and Toughness, J. Mater. Sci., 17, 2371-2383 (1982). 

High stiffness ceramic fibers such as alumina, alumina-silica, silicon carbide, boron, etc. are used as reinforcement fibers for polymeric, metallic, and ceramic matrix composites (Chawla, 1987). Silicon carbide whisker reinforced alumina composites are used as high speed cutting tools (Chawla, 1993). 

Silicon carbide has attracted considerable interest because of its good mechanical and physical properties and chemical inertness. One of the most important applications of SiC is to produce a matrix reinforced by fibres, forming ceramic-matrix composites. These composite materials exhibit much better fracture toughness than monolithic ceramics. Compared with carbon/carbon composites, fibre-reinforced SiC matrix composites possess superior oxidation resistance and mechanical properties. The Si-C-H-Cl system (e.g. methyltrichlorosilane, CH3SiCl3) has been used for SiC deposition because it is easy to produce stoichiometric SiC deposits. 

E. Tani, K. Shobu, and K. Kishi, Two-dimensional-woven-carbon-fiber-reinforced Silicon Carbide/Carbon Matrix Composites Produced by Reaction Bonding, J. Am. Ceram. Soc., 82 [5] 1355-57(1999). 

Ceramic-matrix composites are utilised to overcome the inherent brittleness of ceramics. The reinforcement consists of fibres or particles. The materials used include silicon carbide and alumina. The toughening comes about because the fibres or particles deflect or bridge cracks in the matrix. 

Carbides and nitrides of transition metals are usually hard and some of them are used as hard materials. Tungsten carbide, which was briefly described above, is a major component of cutting tools and wear-resistant materials. Titanium carbide. Tie, and nitride, TiN, are two other major hard materials that are widely used in tools. They also find application as hard coatings (in particular, TiN [177]) and components of ceramic matrix composites [178]. Both TiC and TiN show a very... 

This work reports the development of a polymeric/sol-gel route for the deposition of silicon carbide and silicon oxycarbide thin films for applications such as heat-, corrosion-, and wear-resistant coatings, coatings on fibers for controlling the interaction with the matrix in ceramic matrix composites, or films in electronic and optoelectronic devices. This method, in which the pre-ceramic films are converted to a ceramic coating either by a conventional high temperature annealing or by ion irradiation, is alternative to conventional methods such as chemical or physical vapor deposition (CVD, PVD), molecular beam epitaxy, sputtering, plasma spray, or laser ablation, which are not always practical or cost efficient. 

Due to the tailored properties of liquid phase sintered silicon carbide (LPSSiC) it is used as dewatering elements in the paper machinery and as rings for highly stressed gas seals. It is a price competitive alternative to silicon nitride materials and outperforms alumina and tungsten carbide materials. In addition, LPSSiC is proposed as neutral matrix in ceramic matrix composites containing plutonium to burn the world s stockpiles of military plutonium in thermal or fast reactors [278]. 

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