Elastic silicon carbide

An important application of polydimethylsilane is as a source of silicon carbide (SiC) fibres, which are manufactured under the trade-name Nicalon by Nippon Carbon in Japan. Heating in an autoclave under pressure converts polydimethylsilane to spinnable polycarbosilane (-Me2Si-CH2-) with elimination of methane. The spun fibres are then subjected to temperatures of 1200-1400 °C to produce silicon carbide fibres with very high tensile strengths and elastic moduli." As a result of their conductivity, polysilanes have also been used as hole transport layers in electroluminescent devices. In addition, the photoconductivity of polymethylphenylsilane doped with Cgo has been found to be particularly impressive. ... 

Armor. Silicon carbide is used as a candidate in composite armor protection systems. Its high hardness, compressive strength, and elastic modulus provide superior ballistic capability to defeat high velocity projectile threats. In addition, its low specific density makes it suitable for applications where weight requirements are critical (11). 

The elastic modulus of sintered silicon carbide with 5 % porosity is 468.9 GPa. What is the porosity of a specimen with an elastic modulus of 350 GPa ... 

M-J. Pan, Microcracking Behavior of Particulate Titanium Diboride-Silicon Carbide Composites and Its Influence on Elastic Properties, Ph.D. Thesis, The Pennsylvania State University, 1994. 

Alumina is the most important oxidic abrasion-resistant material. Metal carbides are in some ways superior to oxides with respect to hardness and melting point, but they are much more brittle than the oxides and are only used in isolated instances as wearing bodies. Silicon carbide is characterized by its low thermal expansion and high thermal conductivity and has proved to be more resistant to thermal shock than oxides. Zirconia is tougher than alumina its modulus of elasticity is only about half as large, and it is comparable with that of steel. Zirconia is therefore very suitable for compound structures with steel. At present, the applications of ceramic sintered materials in chemical plant construction are slide rings, pump parts, and slide bearings. 

Silicon carbide is noted for its extreme hardness [182-184], its high abrasive power, high modulus of elasticity (450 GPa), high temperature resistance up to above 1500°C, as well as high resistance to abrasion. The industrial importance of silicon carbide is mainly due to its extreme hardness of 9.5-9.75 on the Mohs scale. Only diamond, cubic boron nitride, and boron carbide are harder. The Knoop microhardness number HK-0.1, that is the hardness measured with a load of 0.1 kp (w0.98N), is 2600 (2000 for aAl203, 3000 for B4C, 4700 for cubic BN, and 7000-8000 for diamond). Silicon carbide is very brittle, and can therefore be crushed comparatively easily in spite of its great hardness. Table 8 summarizes some typical physical properties of the SiC ceramics. 

Wood-based composites with a phenohc resin matrix have been transformed into silicon-infiltrated silicon carbide ceramics by carbonization at about 1 650°C [46]. The bending strength and the elastic modulus of these original ceramics were better than those of conventionally manufactured counterparts, whereas the fracture toughness was lower. 

Silicon carbide (1893) (SiC) n. In the form of crystals, produced in an electric furnace by reaction of carbon with sand, silicon carbide is a dense, extremely hard filler, used in some plastics to increase abrasion resistance, elastic modulus, and thermal conductivity. 

The vibrational method is used in order to condense powders formed from hard and elastic metals and alloys (titanium, molybdenum, silicon carbide, etc.). Here not only are the fine particles distributed between the large ones, but the autohesion is increased... 

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