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Method of coating carbon filaments with silicon carbide - Patent 4131697 A coating of silicon carbide is formed on carbon filaments by passing the heated filaments into an atmosphere of hydrogen and silicon tetrachloride to deposit silicon, and then into a silicon carbide-forming atmosphere. C, into a first reactor containing gaseous silicon tetrachloride and hydrogen, the dwell time of the filament in the first reactor being less than 30 seconds, thereby forming a layer of silicon carbide having a thickness of less tha 0.2 micron, and then passing the filament heated to a temperature of at least 1100.degree. It is also known to coat filaments of certain refractory metals such as tungsten with silicon carbide by passing an electric current through the filament to heat it by the Joule effect, and passing the heated filament through a reactor in which is a mixture consisting of, for example, methyltrichlorosilane and hydrogen. www.freepatentsonline.com /4131697.html   (1077 words)

LBNL MSD - De Jonghe/Silicon Carbide Ceramic The coating prevents the alpha silicon carbide platelets from assisting in the transformation of the beta to alpha silicon carbide, a transformation that would lead normally to the loss of the identity of the platelets during the high temperature processing. The simultaneous increase in the fracture strength and fracture toughness of silicon carbide ceramics is significant. Silicon carbide ceramics have some of the best high temperature characteristics of ceramics, but their extreme brittleness has hindered their practical application. www.lbl.gov /msd/PIs/DeJonghe/94/SiC94Hi.html   (375 words)

Book Review of Silicon Carbide: Recent Major Advances It was at ATMI (1998—2001), while serving as director of operations in the GaAs Epitaxial Services Group (Epitronics), that I had my initiation into the use of gallium nitride (GaN) and silicon carbide (SiC) materials for electronic device applications. To that end, the book Silicon Carbide: Recent Major Advances is a good compendium of advances made since the early 1990s at numerous reputable international institutions by top authorities in the field. He holds six patents and, in the past 25 years, has published in the areas of gallium arsenide integrated circuits and strained silicon metal oxide semiconductor materials and devices. www.aip.org /tip/breview/br19.html   (444 words)

Dynamic Ceramic – Silicon Carbide Engineering Ceramics SiC - RBSC Silicon carbide materials exhibit good erosion and abrasive resistance, these properties can be utilised in a variety of applications such as spray nozzles, shot blast nozzles and cyclone components. Silicon Carbide is derived from powder or grain, produced from carbon reduction of silica. The first method is to mix silicon carbide powder with another material such as glass or metal, this is then treated to allow the second phase to bond. www.dynacer.com /silicon_carbide.htm   (249 words)

Spartanburg SC | GoUpstate.com | Spartanburg Herald-Journal   (Site not responding. Last check: ) Silicon carbide () is a ceramic compound of silicon and carbon and occurs in nature as the extremely rare mineral moissanite. Silicon carbide is often used as a layer of the TRISO coating for the nuclear fuel elements of high temperature gas cooled reactors or very high temperature reactors such as the Pebble Bed Reactor. 90% silicon carbide is used by the steel industry as a ladle deoxidizer, a source of silicon and carbon in the ladle, an electric furnace slag deoxidizer, and as a synthetic slag additive. www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=Silicon_carbide   (2855 words)

Science Fair Projects - Silicon carbide Silicon carbide (SiC) or moissanite is a ceramic compound of silicon and carbon. Most silicon carbide is man-made for use as an abrasive (when it is often known by the trade name carborundum), or more recently as a semiconductor and moissanite gemstones. Silicon carbide is used for blue LEDs, ultrafast Schottky diodes and MESFETs. www.all-science-fair-projects.com /science_fair_projects_encyclopedia/Carborundum   (476 words)

[No title] Baumann observed that although [beta]-silicon carbide began to transform to [alpha]-silicon carbide slowly at 2,100[deg] C, the reaction was rapid at 2,300[deg] C.The suggestion that the transformation from the cubic form to the hexagonal form may proceed via the vapour phase has been made by Slack5. From the work of Drowart et Z., an estimate of the heat of vaporization of silicon carbide at 2,149 and at 2,316 C may be obtained by considering the partial molal equation for the total heat of reaction (?H) to form the various gaseous species from solid silicon carbide. The estimated activation energy of 158 kcal mole-1 (20 per cent) for the b-silicon carbide to a-silicon carbide transformation as deduced from Baumann's data is not in disagreement with the value of 133 kcal mole?1 for the calculated heat of vaporization of gaseous species from silicon carbide. www.nature.com /nature/journal/v199/n4890/ris/199278b0refs.ris   (1166 words)

Silicon carbide - Definition, explanation Silicon carbide (SiC), also known as carborundum or moissanite, is a ceramic compound of silicon and carbon. Electroluminescence of silicon carbide was observed by Captain Henry Joseph Round in 1907 and by O.V. Lossev in the Soviet Union in 1923 [1]. Silicon carbide is a popular product in modern lapidary due to the durablility and low cost of the material. www.calsky.com /lexikon/en/txt/s/si/silicon_carbide.php   (774 words)

Nanosized silicon carbide – dispersed alumina ceramics prepared by pressureless sintering   (Site not responding. Last check: ) The first alumina-silicon carbide nanocomposites, produced mainly by hot-pressing, were reported to have improved microstructures and mechanical properties [1-6]. In alumina-silicon carbide nanocomposites, most of the researchers observed a so-called intra/intern type of microstructure, that is most of the SiC particles, typically less than 0.2 mm, were predominantly dispersed within the matrix grains but with some larger SiC particles at the grain boundaries and triple point junctions [1,2,7-9]. When using dopants, to provide conditions for liquid phase sintering, an alumina/silicon carbide nanocomposite can be sintered to high densities at temperatures as low as 1300°C. The densification behaviour and microstructural development of a 5vol% silicon carbide dispersed alumina nanocomposite were studied by incorporating six different oxide dopants (1wt%). www.ul.ie /~mst/stuart/research/Alumina%20SiC%20Nanocomposite.htm   (470 words)

Materials — Silicon Carbide (SiC) Properties Silicon carbide is an excellent abrasive and has been produced and made into grinding wheels and other abrasive products for over one hundred years. Silicon carbide is composed of tetrahedra of carbon and silicon atoms with strong bonds in the crystal lattice. Silicon carbide ceramics with little or no grain boundary impurities maintain their strength to very high temperatures, approaching 1600°C with no strength loss. www.accuratus.com /silicar.html   (281 words)

Silicon Carbide - Reaction Bonded Silicon Carbide (RBSC) Apart from its main uses in metallurgy, abrasives and refractories, silicon carbide is also used in structural applications where high temperature strength or high stiffness to weight ratios are required. Although silicon carbide can be densified with high temperature and pressure, the process is not a viable commercial process. Reaction bonded silicon carbide is made by infiltrating compacts made of mixtures of SiC and carbon with liquid silicon. www.azom.com /details.asp?ArticleID=147   (684 words)

Silicon Carbide (SiC) Silicon carbide is a hard covalently bonded material predominantly produced by the carbothermal reduction of silica (typically using the Acheson process). The outline properties of Silicon Carbide are that it is a refractory material (high melting point), it has excellent thermal conductivity and low thermal expansion, consequently it displays good thermal shock resistance. Silicon carbide possesses interesting electrical properties due to its semiconductor characteristics, the resistance of different compositions varying by as much as seven orders of magnitude. www.azom.com /details.asp?ArticleID=42   (416 words)

silicon carbide,alpha silicon carbide manufacturer and silicon carbide,alpha silicon carbide supplier--China Ningbo ... Established in 1998, China Ningbo LIHE INC. is a professional manufacturer and exporter of all kinds magnets, silicon carbide, alpha silicon carbide and mechanical seals, dedicated to satisfying customers by providing wide range magnetic products and relative services. Through years of endeavors, the company has already become a leading manufacturer in magnets, silicon carbide, alpha silicon carbide, mechanical seal, sic, pressless sic and mechanical seals. Silicon carbide has good corrosion resistance, high hardness, excellent thermal conductivity properties and resistance to temperature flucturation. www.lihe-china.com /silicon_carbide.htm   (198 words)

SiC Ceramic Materials — Silicon Carbide Ceramic Materials - Saint Gobain - Hexoloy - Carborundum Hexoloy® SE Silicon Carbide – produced in a proprietary extrusion process with extreme hardness and high strength for severe environment applications. Hexoloy® SG Silicon Carbide – a unique electrically conductive analog of sintered silicon carbide. Enhanced Hexoloy® SA Silicon Carbide – exhibits reduced microporosity which results in increased flexural strength and a higher Weibull modulus. www.carbo.com   (221 words)

Mayne Island Glass Foundry - 170-pound Silicon Carbide Electric Glass Furnace The Silicon Carbide rods have a 23" heating zone which is the width of the heating chamber. Silicon Carbide has a strange resistance temperature curve. As the furnace heats up, it runs as high as 14,000 watts, but as it reaches operating temperature, this drops to around 11,000. www.mayneislandglass.com /170lbinvestedsicfurnace.htm   (1918 words)

Tekes Partner Search - Results The coating is made of a continuous layer of silicon oxide generated by controlled oxidation of the silicon carbide reinforcements or by sol-gel techniques. The coating of the silicon carbide is one of the methods to avoid the interfacial reaction between the aluminium and these particles. The coating technique with silicon oxide used in this technology improves the casting manufacturing process of this kind of composites due to improvement of the wetting behaviour of the particles of silicon carbide during composite manufacturing. www.tekes.fi /partner/eng/search/nayta_haku.asp?hakuid=6859   (727 words)

The Hexoloy Difference — Silicon Carbide Ceramic Materials - Saint Gobain - Hexoloy - Carborundum Hexoloy sintered alpha silicon carbide is produced by pressureless sintering ultra-pure submicron powder derived from the original Acheson process. Hexoloy silicon carbide is one of the hardest high performance materials available, second only to diamonds. The high density, low porosity and chemical inertness of Hexoloy silicon carbide permit it to function in environments of hot gases and liquids, in oxidizing and corrosive atmospheres, and in strong acids and bases, even at extremely high temperatures. www.carbo.com /hexoloy-difference?referred=google_SiC_silicone_carbide   (600 words)

Silicon Carbide (SiC) Morgan Advanced Ceramics Is a silicon infiltrated reaction bonded impervious silicon carbide with a very high thermal conductivity, mechanical strength, corrosion resistance and an excellent thermal shock resistance. Is a pressure less sintered silicon carbide with a very high thermal conductivity, mechanical strength and an excellent thermal shock resistance similar to Halsic-I, but with a working temperature of 1600oC. Is a re-crystallised silicon carbide with an open pore structure and a coarse grain. www.morganadvancedceramics.com /materials/sc.htm   (500 words)

BBC NEWS | Science/Nature | Door open for silicon replacement Silicon carbide (SiC) could be used to make electronic devices that can operate at high power, in fierce heat or at lethal doses of radiation. Silicon wafers are then chemically "doped" with impurities to improve their ability to carry an electrical charge. One exciting application for silicon carbide could be in deep-space missions, where nuclear power would be needed for the craft. news.bbc.co.uk /2/hi/science/nature/3598836.stm   (590 words)

Silicon Carbide Elements The heating section, a self-bonded silicon carbide structure of large crystals uniformly and strongly bonded together, is dimensionally stable, so its length never varies with use. However, because of the high thermal conductivity of the silicon carbide, heat migrates from both ends of the heating sections creating a slightly longer effective heating section or hot zone. Because of the high thermal conductivity of the silicon carbide, heat migrates from both ends of the heating section creating a slightly longer effective heating section or hot zone. www.megsystems.com /Products/custom_elements/silicon_carbide_elements/silicon_carbide_elements.html   (734 words)

Silicon Carbide Microsensors for Demanding Applications - As MEMS sensors move into more extreme environments, the ... Silicon Carbide Microsensors for Demanding Applications - As MEMS sensors move into more extreme environments, the search for an alternative to silicon is on. Silicon carbide is uniquely suited to use in harsh environment sensors. While silicon (specifically, silicon on insulator, or SOI) and GaAs can be pushed to reasonably high operating temperatures (~300°C) and radiation fluxes (1 Mrad), these two materials are not well suited for harsh mechanical and chemical environments. www.sensorsmag.com /sensors/article/articleDetail.jsp?id=186852   (663 words)

Silicon Carbide vs Tungsten Carbide by Jason Fletcher Seal options include a stationary silicon carbide face and a rotating carbon face or a stationary carbide face and a rotation silicon carbide face. Silicon carbide faces should be used in any environment where a ceramic/carbon combination would not be suitable (i.e. Silicon Carbide is now manufactured at such a high volume that the price is considerably cheaper and the lead times are shorter than an equal tungsten carbide seal. www.zoeller.com /Zep/Techbrief/JF4article.htm   (444 words)

PECVD Silicon Carbide Amorphous   (Site not responding. Last check: ) The interest in this material is due to its likeness with the silicon carbide crystalline (c-SiC) whose notable properties, to know, high mechanical hardness and chemical stability, release band forbidden, high thermal conductivity and high rupture tension, etc., they wake up great interest in as several as the microeletronic areas, metalurgia and medicine (orthopedics). Silicon Carbide obtained by PECVD (a-SiC:H) Of the point of view of the obtaining technique, the main appeals of the a-SiC:H obtained by PECVD they are the low temperatures in that the material can be obtained. The amorphous silicon for example, became only useful as semiconductor after the discovery that atoms of hydrogen can saturate the incomplete connections in its structure, reducing like this the density of states located in the forbidden band. www.stormpages.com /aro/pagemestrado.htm   (2192 words)

Tangali Sudarshan silicon carbide research Scientists have discovered that silicon carbide is nearly immune to such conditions, making it an ideal choice for a new generation of semiconductors that can be used on satellites, in automobile electronics, and in other extreme conditions. It’s not as simple as it might sound: silicon carbide is commonly used as an abrasive, so polishing the material in its wafer form is like trying to make sandpaper smooth. Finally, the team is developing a controlled porosity on the surface of silicon carbide wafers that would allow its use in optical and gas sensors in harsh environments. www.sc.edu /usctimes/articles/2003/2003-05/sudarshan_silicon_carbide.html   (548 words)

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