Properties of Silicon Carbide

Fabrication by Liquid Silicon Infiltration (reaction bonding) (LSI) A leading candidate for use in industrial gas turbine engine is a SiC matrix composite named toughened Silcomp [175]. It is produced by melt infiltration of molten silicon into a porous preform containing carbon as well as BN-coated SiC fibers (e.g. Textron SCS - 6). The composites thus produced consist of a fully dense matrix of SiC + Si, reinforced with continuous SiC fibers. Moreover, the melt infiltration process is net shape and fast. Ultimate strength and strain at ultimate strength are 220 MPa and 0.8 /o, respectively at room temperature (LSI-SiC/SiC Si). 

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For example. Properties of Silicon Carbide, Harris, G.L., Ed. EMIS Datareviews Series No. 13 INSPEC Publication, lEE London, 1995. 

The properties of silicon carbide (4—6) depend on purity, polytype, and method of formation. The measurements made on commercial, polycrystalline products should not be interpreted as being representative of single-crystal silicon carbide. The pressureless-sintered silicon carbides, being essentially single-phase, fine-grained, and polycrystalline, have properties distinct from both single crystals and direct-bonded silicon carbide refractories. Table 1 lists the properties of the fully compacted, high purity material. 

Sintered silicon carbide retains its strength at elevated temperatures and shows excellent time-dependent properties such as creep and slow crack growth resistance. Reaction-bonded SiC, because of the presence of free silicon in its microstructure, exhibits slightly inferior elevated temperature properties as compared to sintered silicon carbide. Table 2 (11,43) and Table 3 (44) show selected mechanical properties of silicon carbide at room and elevated temperatures. 

Electrical Properties. The electrical properties of silicon carbide are highly sensitive to purity, density, and even to the electrical and thermal... 

R. T. Bhatt, The Properties of Silicon Carbide Fiber-Reinforced Silicon Nitride Composites , in Whisker- and Fiber-Toughened Ceramics, eds. R. A. Bradley, D. E. Clark, D. C. Larsen, and J. O. Stiegler, ASM, Materials Park, PA, 1988, p. 199. 

L. P. Zawada, L. M. Butkus, and G. A. Hartman, Room Temperature Tensile and Fatigue Properties of Silicon Carbide Fiber-Reinforced Aluminosilicate Glass, Cer. Eng. Sci. Proc., 11[9-10], 1592-1606 (1990). 

Hoppe P., Strebel R., Eberhardt P., Amari S., and Lewis R. S. (2000) Isotopic properties of silicon carbide X grains from the Murchison meteorite in the size range 0.5—1.5 p,m. Meteorit. Planet. Sci. 35, 1157-1176. 

The bulk analysis of /3-SiC whiskers shows the least variation in chemistry. In some whiskers, the residual metals content can vary, most likely, as a result of additives that used as catalysts during synthesis. These include iron, cobalt, and chromium. Studies by Karasek et al. [56] have shown that the physical properties of silicon carbide whisker-reinforced composites do not correlate to the bulk properties of the whiskers significantly. This lack of significant correlation is mainly due to the fact that the important phase chemistry of the whisker-matrix interface is controlled by the matrix chemistry and the surface chemistry of the whiskers. There seems to be little impact of the diffusion of materials into or out of the bulk whisker material. 

Huang, Q. et al.. Effect of pretreatment on rheological properties of silicon carbide aqueous suspension, Ceram. Int., 28, 747, 2002. 

Iskra, J., Flotation properties of silicon carbide. 1. Flotation of silicon carbide with anionic and cationic collector, Ceram. Int., 23, 337, 1997. 

It is highly probable that the metal contamination strongly affects the electrical properties of silicon carbide crystals and reduces the carrier lifetimes, as in other semiconductors. Unfortunately, no detailed studies of this effect have been reported thus far. 

PROPERTIES OF SILICON CARBIDE CERAMIC FROM GELCASTING AND PRESSURELESS SINTERING... 

Properties of Silicon Carbide Ceramic from Gelcasting and Pressureless Sintering... 

Hirao, T. Hamano, T. Sakai, T. Nashiyama, I. Nucl. Instrum. Methods, 1999, B158, 260. For example. Properties of Silicon Carbide, Harris, G.L., Ed. EMIS Datareviews Series No. 13 INSPEC Pubhcation, lEE London, 1995. 

Fiset, E., J. S. Bae, T. E. Rufford, S. Bhatia, G. Q. Lu, and D. Hulicova-Jurcakova. 2014. Effects of structural properties of silicon carbide-derived carbons on their electrochemical double-layer capacitance in aqueous and organic electrolytes. Journal of Solid State Electrochemistry 18 703-711. 

Properties of Silicon Carbide- and Boron Carbide-Based Materials 183... 

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