Silicon carbide whisker reinforcement

Silicon carbide whisker-reinforced glass and glass-ceramic composites... 

K. P. Gadjaree and K. Chyung, Silicon Carbide Whisker Reinforced Glass and Glass-Ceramic Composites, Am. Ceram. Soc. Bull., 65[2], 370-376 (1986). 

G. C. Wei (U.S. Dept, of Energy), Silicon Carbide Whisker Reinforced Ceramic Composites and Method for Making Same, U.S. Patent 4,543,345, September 24, 1985. 

S. R. Choi, et al., Dynamic FatigueProperty of Silicon Carbide Whisker-Reinforced Silicon Nitride, Ceram. Eng. Sci. Proc., 12[7-8], 1524-1536 (1991). 

J. R. Porter and A. Chokshi, Creep Performance of Silicon Carbide Whisker-Reinforced Alumina in Ceramic Microstructures 86 The Role of Interfaces, eds. J. Pask and A. Evans, Plenum Press, New York, NY, 1987, p. 919. 

E. R. Fuller, Jr., R. F. Krause, Jr., J. Kelly, R. N. Kacker, E. S. Lagergren, P. S. Wang, J. Barta, P. F. Jahn, T. Y. Tien, and L. Wang, Microstructure, Mechanical Properties, and Machining Performance of Silicon Carbide Whisker-Reinforced Alumina, J. Research NIST, in press. 

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). 

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. 

B. J. Wrona, J. F. Rhodes, andW. M. Rogers, Silicon Carbide Whisker Reinforced Alumina, Ceram. Eng. 

L. Chen, C. Leonelli, T. Manfredini, C. Siligardi, Processing of Silicon Carbide Whisker-Reinforced Glass-... 

If this carbothermal process is brought to only partial completion (Equation 11a and 11b), a homogeneous mixture of silicon carbide whiskers and silicon nitride powder [10] is obtained which can be fired directly to yield whisker reinforced ceramics. Silicon carbide reinforced alumina composites and silicon carbide whisker reinforced zirconia composites [31] are also products of the "chemical mixing process". The whisker growth rate in the zirconia process can be accelerated by adding metal particle catalysts such as cobalt chloride, thus potentially facilitating a VLS phase transformation. 

Jing Wang, Litong Zhang, Laifei Cheng et al. Preparation and mechanical properties of silicon carbide whisker reinforced silicon carbide mini composites. Journal of Aeronautical Materials, 29(1) 68-71, 2009. 

Zhang, X. H., Xu, L., Han, W. B., Weng, L., Han, J. C. (2009). Microstmcture and properties of silicon carbide whisker reinforced zirconium diboride ultra-high temperature ceramics. Solid State Sciences, 11,156-161. doi 10.1016/j.solidstate-sciences.2008.05.010. 

Other ceramic cutting-tool materials include alumina, Si-Al-0-N, alumina-carbide composites and, more recently, a composite of silicon nitride reinforced with silicon carbide whiskers. This last material can be produced by chemical-vapor infiltration (CVI) and has high strength and toughness as shown in Table 18.3.Cl... 

More recently, Stanicioiu, Chinta Hartner (1959) attempted to reinforce the cement with glass fibres, but this was not successful. The most serious study on the reinforcement of dental silicate cement was made by J. Aveston (in Wilson et al., 1972). Silicon carbide whiskers, carbon fibres and alumina powder were introduced into the cement mix. Unfortunately, the glass powder/liquid ratio had to be reduced, and the strength gained by reinforcement was thereby lost. It is clear that dental silicate cement cannot be strengthened by fibre or particulate reinforcement. 

P. F. Becher and T. N. Tiegs, Elevated-Temperature-Delayed Failure of Alumina Reinforced with 20 vol% Silicon Carbide Whiskers, J. Am. Ceram. Soc., 73[1], 91-96 (1990). 

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. 

A. H, Chokshi and J. R. Porter. "Creep Deformation of an Alumina Matrix Composite Reinforced with Silicon Carbide Whisker," J. Am. Ceram, Soc, 68(6), C-144-145 (1985). 

Becher, P. F., Heueh, C., Angellita, P., and Tiegs, T. N. (1988). Toughening behavior in whisker-reinforced ceramic matrix composites. / Am. Ceram Soc. 71 1051-1061. Homeny,J., Vaughn, W. L., and Ferber, M. K. (1990). Silicon carbide whisker/alumina matrix composites effect of whisker surface treatment on fracture toughness./ Am Ceram. Soc. 73 394-402. 

Ueno, K., and Toibana, Y. (1983). Mechanical properties of silicon nitride ceramic composite reinforced with silicon carbide whisker. Yogyo-Kyokai-Shi 91 491-497 (in Japanese). 

Mixed ceramics are available where the addition of cubic carbides or carbonitrides improves toughness and thermal conductivity. Whisker-reinforced ceramics use silicon carbide whiskers to dramatically increase toughness and enable the use of a cutting fluid. 

Ceramics, particularly new ceramic composites, are widely used in the cutting-tool industry. For example, alumina reinforced with silicon carbide whiskers (extremely fine fibers) is used to cut and machine cast iron and harder nickel-based alloys. Ceramic materials are also used in grinding wheels and as abrasives because of tiieir exceptional hardness (Table 12.4). Silicon carbide is the most widely used abrasive. 

Because axial turbine rotors made of Si3N4 are still not completely reliable, research efforts continue to focus both on improving injection molding techniques and on strengthening the silicon nitride material systems. A ee-ramic composite of Si3N4 reinforced with silicon carbide whiskers may reduce structural failures and provide better high-temperature performance than monolithic ceramic parts. 

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