Material silicon carbides

Flameholder - Flameholders are necessary to prevent the flame from "riding" up to the top of the stack. They provide a surface at which burning can take place and also promote better mixing of air and gas by the additional turbulence which they cause above the jets. Construction is simply a solid, 25 mm diameter rod of refractory material (silicon carbide) supported horizontally above each burner line. The bottom of the rod should be 13 mm above the tips of the jets. 

Silicon-based materials (silicon carbide, silicon nitride) usually form a superficial film of silicon dioxide that protects the material against corrosion in acidic or neutral media. At pH equal to or higher than eleven it suffers corrosion heavily because the silicon dioxide is dissolved [25],... 

As observed by D. Johnson and J. Stiegler, "Polymer-precursor routes lor fabricating ceramics offer one potential means or producing reliable, cost-effective ceramics. Pyrolysis of polymeric metalloorganic compounds can be used to produce a wide variety of ceramic materials." Silicon carbide and silicon oxycarbide fibers have been produced and sol gel methods have been used In prepare line oxide ceramic powders, such as spherical alumina, as well as porous and fully dense monolithic forms. 

Peugeot Fuel additive, ignition temperature 450 °C. Increase of exhaust temperature by exhaust port injection. Filter material silicon carbide... 

When carbon forms compounds with other atoms having rather high electronegativity (Si, B, etc.), the bonds are considered to be covalent. The compounds formed, especially SiC, have the characteristics of being hard, unreactive refractory materials. Silicon carbide has a structure similar to diamond, and it is widely used as an abrasive material. It is prepared by the reaction of Si02 with carbon ... 

This chapter discusses the behavior, under thermal shock conditions, of epoxy resins toughened with ceramic particulates. Alumina Al203 and silica Si02, which are usually used as filler for insulation materials, and the new ceramic materials silicon carbide SiC and silicon nitride Si3N4 are employed. For these toughened epoxy resins, the thermal shock resistance is evaluated by using fracture mechanics. The difference between experimental and calculated values of the thermal shock resistance is discussed from a fractographic point of view. 

For a ceramic material, silicon carbide has an unusually high thermal conductivity 150 WmK- at 20°C and 54 WraK at 1400°C [180], The high thermal conductivity and low thermal expansion (4.7 x 10 K for 20-1400°C) explain why the material has such good resistance to thermal shock. 

Rzany, A., Schaldach, M. Smart material silicon carbide reduced activation of cells and proteins on a-SiC H-coated stainless steel. Prog. Biomed. Res. 3, 182-194 (2001)... 

Chemical vapor infiltration (CVI) is a CVD variant capable of internally coating porous objects, e.g., an object made out of carbon fibers, with a ceramic material. Silicon carbide (SiC) or boron carbide (B4C) are examples of ceramic matrix materials that are used in combination with carbon fibers. Strong, light, durable, wear-resistant, and biocompatible joint prostheses made of ceramic-ceramic composites are manufactured by means of CVI. Figure 6.18 shows how the degree of penetration is affected by temperature and pressure. Clearly, to get deposit deep in the interior of the porous object low temperatures are necessary for reaction limitation and low pressures for helping the diffusion. Under these conditions growth rates are low. 

Nonmetallic Heating Element Materials Silicon carbide, SiC 1 to 1.7... 

This chapter deals with the noncatalytic hydrodesulfurization (NHDS), hydrodemet-allization (NHDM), and hydrocracking (NHDC) of heavy crude oil and atmospheric residue. Some experiments were carried out in two different bench-scale units equipped with fixed-bed reactors in series operated in adiabatic and isothermal modes. The reactors were loaded with inert material (silicon carbide). Different feedstocks were used for the tests 13°API heavy crude oil, 21°API crude oil, atmospheric residue from the 13°API heavy crude oil, and atmospheric residue from the 21°API crude oil. The effects of pressure, residence time, temperature, and type of feed on noncatalytic reactions and axial reactor temperature profiles are examined. Reaction kinetics of the different noncatalytic reactions is studied by following the power-law approach. 

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