Strength silicon carbides

Prewo, K.M. and Brennan, J J., High strength silicon carbide fibre reinforced glass-matrix composites , J. Mat. Sci., 15, 463 168 (1980). 

K. M. Prewo and J. J. Brennan, High Strength Silicon Carbide Fiber-Reinforced Glass Matrix Composites, J. Mater. Sci., 15, 463-468 (1980). 

Prewo, K.M., and J.J. Brennan. 1980. High-strength silicon carbide fiber reinforced glass-matrix composites. Journal of Materials Science 15 463 68. ... 

Yajima, S., Hasegawa, Y, Okamura, K., Matsuzawa, T. (1978b). Development of high-tensile strength silicon-carbide fiber using an organosiliconpol3mier precursor. Nature, 273(5663), 525-527. doi 10.1038/273525a0. 

The formation of silicon carbide, SiC (carborundum), is prevented by the addition of a little iron as much of the silicon is added to steel to increase its resistance to attack by acids, the presence of a trace of iron does not matter. (Addition of silicon to bronze is found to increase both the strength and the hardness of the bronze.) Silicon is also manufactured by the reaction between silicon tetrachloride and zinc at 1300 K and by the reduction of trichlorosilane with hydrogen. 

Properties of Dense Silicon Carbide. Properties of the SiC stmctural ceramics are shown in Table 1. These properties are for representative materials. Variations can exist within a given form depending on the manufacturer. Figure 2 shows the flexure strength of the SiC as a function of temperature. Sintered or sinter/HIP SiC is the preferred material for appHcations at temperatures over 1400°C and the Hquid-phase densified materials show best performance at low temperatures. The reaction-bonded form is utilized primarily for its ease of manufacture and not for superior mechanical properties. 

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... 

Silicon carbide CVD Sol-gel High strength High modulus High cost High-temp composites... 

Figure 19.3. Tensile strength of CVD silicon-carbide fiber as a function of temperature.

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. 

Soluble polysilane polymers can also be used as precursors to silicon carbide. The first such application, using (PhMeSi)n-(Me2Si)m copolymers ("Polysilastyrene"), was to strengthen silicon nitride ceramics. The Si3N4 ceramic body was soaked in polysilane and refired, leading to the formation of silicon carbide whiskers in the pore spaces and a consequent increase in strength. (U)... 

Silicon carbide, SiC [1] and silicon nitride, Si3N4 [2], have been known for some time. Their properties, especially high thermal and chemical stability, hardness, high strength, and a variety of other properties have led to useful applications for both of these materials. 

Flexural modulus, 10 177, 223, 224 of filled polymers, 11 303 Flexure strength, of silicon carbide, 22 528t FLExX, 6 13 FlexX method, 10 337 Flicker noise, silicon-based semiconductors and, 22 237 Flint, 5 640 22 480... 

Fracture strength, of vitreous silica, 22 428 Fracture tests, 1 514 Fracture toughness ceramics, 5 619-623 of silicon carbide, 22 528t of vitreous silica, 22 429 Fracture toughness tests, 10 427 Fracture toughness values... 

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