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Encyclopedia > Silicon carbide
Silicon carbide
Identifiers
CAS number 409-21-2
Properties
Molecular formula SiC
Molar mass 40.097 g/mol
Appearance black-green odorless powder
Density 3.22 g/cm³, solid
Melting point

2730°C Image File history File links Download high-resolution version (1080x1100, 266 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Silicon carbide ... Synthetic silicon carbide crystal aggregate. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...

Solubility in water insoluble
Hazards
EU classification not listed
NFPA 704

Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Council Directive 67/548/EEC of 27 June 1967 on the approximation of laws, regulations and administrative provisions relating to the classification, packaging and labelling of dangerous substances (as amended) is the main European Union law concerning chemical safety. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... Image File history File links NFPA_704. ...

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Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Silicon carbide (SiC) is a ceramic compound of silicon and carbon that is manufactured on a large scale for use mainly as an abrasive but also occurs in nature as the extremely rare mineral moissanite. In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... Not to be confused with Silicone. ... For other uses, see Carbon (disambiguation). ... Fixed Partial Denture, or Bridge The word ceramic is derived from the Greek word κεραμικός (keramikos). ... A chemical compound is a chemical substance of two or more different chemically bonded chemical elements, with a fixed ratio determining the composition. ... Not to be confused with Silicone. ... For other uses, see Carbon (disambiguation). ...

Contents

Production

Due to the rarity of natural moissanite, silicon carbide is typically man-made. Most often it is used as an abrasive where it is often known by the trademark carborundum, and more recently as a semiconductor and diamond simulant of gem quality. The simplest manufacturing process is to combine silica sand and carbon in an Acheson graphite electric resistance furnace at a high temperature, between 1600 and 2500 °C. An abrasive is a material, often a mineral, that is used to shape or finish (see metal polishing and wood finishing) a workpiece through rubbing which leads to part of the workpiece being worn away. ... A semiconductor is a solid whose electrical conductivity is in between that of a conductor and that of an insulator, and can be controlled over a wide range, either permanently or dynamically. ... Due to its low cost and close visual likeness to diamond, cubic zirconia has remained the most gemologically and economically important diamond simulant since 1976. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... For other uses, see Sand (disambiguation). ... For other uses, see Carbon (disambiguation). ...


The material formed in the Acheson furnace varies in purity, according to its distance from the graphite resistor heat source. Clear, pale yellow and green crystals have the highest purity and are found closest to the resistor. The color changes to blue and black at greater distance from the resistor, and these darker crystals are less pure and usually doped with nitrogen, which increases the electrical conductivity of these samples, and with aluminium and/or iron, which decrease conductivity. For other uses, see Graphite (disambiguation). ... Resistor symbols (non-European) Resistor symbols (Europe, IEC) Axial-lead resistors on tape. ... A heating element converts electricity into heat through the process of Joule heating. ... Electrical conductivity or specific conductivity is a measure of a materials ability to conduct an electric current. ... “Aluminum” redirects here. ... For other uses, see Iron (disambiguation). ...


Purer silicon carbide can be made by the more expensive process of chemical vapor deposition (CVD). Commercial large single crystal silicon carbide is grown using a physical vapor transport method commonly known as modified Lely method. DC plasma (violet) enhances the growth of carbon nanotubes in this laboratory-scale PECVD apparatus. ... A single crystal is a crystalline solid in which the crystal lattice of the entire sample is continuous and unbroken to the edges of the sample. ... Physical vapor deposition (PVD) is a technique used to deposit thin films of various materials onto various surfaces (e. ...


Purer silicon carbide can also be prepared by the thermal decomposition of a polymer, poly(methylsilyne), under an inert atmosphere at low temperatures. Relative to the CVD process, the pyrolysis method is advantageous because the polymer can be formed into various shapes prior to thermalization into the ceramic. Thermal decomposition is a chemical reaction where a chemical substance breaks up into at least two chemical substances when heated. ... Poly(methylsilyne) (PMSy) is one of a class of silicon-based random network polymers primarily composed of tetrahedrally hybridized silicon atoms, each having one methyl substituent, exhibiting the generic formula [MeSi]n. ... An inert gas is any gas that is not reactive under normal circumstances. ...


Discovery

The material was manufactured by Edward Goodrich Acheson around 1893, and he not only developed the electric batch furnace by which SiC is still made today but also formed The Carborundum Company to manufacture it in bulk, initially for use as an abrasive. It is said that Acheson was trying to dissolve carbon in molten corundum (alumina) and discovered the presence of hard, blue-black crystals which he believed to be a compound of carbon and corundum: hence carborundum. Or, he named the material "carborundum" by analogy to corundum, which is another very hard substance (9 on the Mohs scale). —Edward Goodrich Acheson (March 9, 1856 - July 6, 1931) was a American chemist. ... A furnace is a device for heating air or any other fluid. ... Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals. ... Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ...


In nature

Naturally occurring moissanite is found only in minute quantities in certain types of meteorite and in corundum deposits and kimberlite. Virtually all of the silicon carbide sold in the world, including moissanite jewels, is synthetic. Natural moissanite was first found in 1893 as a small component of the Canyon Diablo meteorite in Arizona by Dr. Ferdinand Henri Moissan, after whom the material was named in 1905. Moissan's discovery of naturally occurring SiC was initially disputed because his sample may have been contaminated by silicon carbide saw blades that were already on the market at that time. Corundum (from Tamil kurundam) is a crystalline form of aluminium oxide and one of the rock-forming minerals. ... Hewn kimberlite core sample from the James Bay Lowlands region of Northern Ontario, Canada. ... In chemistry, chemical synthesis is purposeful execution of chemical reactions in order to get a product, or several products. ... Year 1893 (MDCCCXCIII) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Tuesday of the 12-day slower Julian calendar). ... The Canyon Diablo meteorite impacted at Barringer Crater, Arizona and is known from fragments collected around the crater and nearby Canyon Diablo which lies about 3 to 4 miles west of the crater. ... Official language(s) English Spoken language(s) English 74. ... Ferdinand Frederick Henri Moissan (September 28, 1852 – February 20, 1907) was a French chemist who won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds. ... For other uses, see 1905 (disambiguation). ... A diamond blade is a circular saw blade used for cutting hard or abrasive materials. ...


Analysis of SiC grains found in the Murchison carbonaceous chondrite meteorite has revealed anomalous isotopic ratios of carbon and silicon, indicating an origin from outside the solar system and closer to the galactic centre.[1]


Properties

Silicon carbide exists in at least 70 crystalline forms. Alpha silicon carbide (α-SiC) is the most commonly encountered polymorph; it is formed at temperatures greater than 2000 °C and has a hexagonal crystal structure (similar to Wurtzite). The beta modification (β-SiC), with a face-centered cubic crystal structure (similar to diamond and zincblende or sphalerite), is formed at temperatures below 2000 °C and is shown in the structure at the top of the page. Until recently, the beta form has had relatively few commercial uses, although there is now increasing interest in its use as a support for heterogeneous catalysts, owing to its higher surface area compared to the alpha form. Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. ... In crystallography, the hexagonal crystal system is one of the 7 lattice point groups. ... Enargite crystals In mineralogy and crystallography, a crystal structure is a unique arrangement of atoms in a crystal. ... Zinc sulfide is a chemical compound with the formula ZnS. Zinc sulfide is a white to yellow colored powder or crystal. ... In crystallography, the cubic crystal system is the most symmetric of the 7 crystal systems. ... One unit cell of the diamond cubic crystal structure. ... Sphalerite sample Another sphalerite sample Sphalerite (ZnS) is a mineral that is the chief ore of zinc. ... Sphalerite sample Another sphalerite sample The unit cell of sphalerite Sphalerite (ZnS) is a gay mineral that is the chief ore of zinc. ...


Silicon carbide has a specific gravity of 3.2, and its high sublimation temperature (approximately 2700 °C) makes it useful for bearings and furnace parts. Silicon carbide does not melt at any known pressure. It is also highly inert chemically. There is currently much interest in its use as a semiconductor material in electronics, where its high thermal conductivity, high electric field breakdown strength and high maximum current density make it more promising than silicon for high-powered devices.[citation needed] In addition, it has strong coupling to microwave radiation, which together with its high melting point, permits practical use in heating and casting metals. SiC also has a very low coefficient of thermal expansion and experiences no phase transitions that would cause discontinuities in thermal expansion. A bearing is a device to permit constrained relative motion between two parts, typically rotation or linear movement. ... Semiconductor materials are insulators at absolute zero temperature that conduct electricity in a limited way at room temperature (see also Semiconductor). ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field. ... In electricity, current refers to electric current, which is the flow of electric charge. ... This article is about the type of Electromagnetic radiation. ... During heat transfer, the energy that is stored in the intermolecular bonds between atoms changes. ... In physics, a phase transition, (or phase change) is the transformation of a thermodynamic system from one phase to another. ...


Pure SiC is clear. The brown to black color of industrial product results from iron impurities. The rainbow-like lustre of the crystals is caused by a passivation layer of silicon dioxide that forms on the surface. For other uses, see Iron (disambiguation). ... Passivation is the process of making a material passive in relation to another material prior to using the materials together. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ...


Uses

Semiconductor

Pure α-SiC is an intrinsic semiconductor with band gaps of 3.28 eV (4H) and 3.03 eV (6H) respectively. An intrinsic semiconductor, also called an undoped semiconductor or i-type semiconductor, is a pure semiconductor without any significant dopant species present. ... This article or section does not adequately cite its references or sources. ...


Possibly the earliest electrical application of SiC was in lightning arresters in electric power systems. These devices must exhibit high resistance until the voltage across them reaches a certain threshold VT, at which point their resistance must drop to a lower level and maintain this until the applied voltage drops below VT. A lightning rod is a metal strip or rod, usually of copper or similar conductive material, used to protect tall or isolated structures (such as the roof of a building or the mast of a vessel) from lightning damage. ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ...


It was recognized early on that SiC had such a voltage-dependent resistance, and so columns of SiC pellets were connected between high-voltage power lines and the earth. When a lightning strike to the line raises the line voltage sufficiently, the SiC column will conduct, allowing the worst of the stroke to pass harmlessly to the earth instead of along the power line. Unfortunately, such SiC columns proved to conduct significantly at normal power-line operating voltages and thus had to be placed in series with a spark gap. This spark gap is ionized and rendered conductive when lightning raises the voltage of the power line conductor, thus effectively connecting the SiC column between the power conductor and the earth, where it then operates as before. Power line redirects here. ... Wikipedia does not yet have an article with this exact name. ... This article or section does not adequately cite its references or sources. ... A spark plug. ... This article is about the electrically charged particle. ...


The trouble here is that spark gaps used in lightning arrestors are notoriously unreliable: they either fail to strike an arc when needed or fail to turn off afterwards: this last is due to material failure or contamination by dust or salt. In fact, the whole idea of using the SiC column was to eliminate the need for the spark gap in a lightning arrester.


But with some intensive engineering, the gapped SiC lightning arrester proved to be a reasonably good lightning-protection tool for many years. There were several brand names; GE and Westinghouse made them, among others. The gapped SiC arrester has been largely displaced by no-gap varistors that use columns of zinc oxide pellets. Ge may refer to: Gê, a group of indigenous Brazilian tribes and their Ge languages Ge (Cyrillic) (Г, г), a letter of the Cyrillic alphabet Ge with upturn (Ґ, ґ), a letter of the Ukrainian alphabet Nikolai Ge, a Russian painter Gē, an ancient Chinese dagger-axe Ge (genus), a genus of butterflies Also... The name Westinghouse can refer to any number of devices and independent businesses that trace their roots to the work of George Westinghouse: People George Westinghouse, founder of Westinghouse Electric Corporation Places George Westinghouse Bridge in East Pittsburgh, Pennsylvania Westinghouse Park in Pittsburgh, Pennsylvania Devices Westinghouse air brake, patented by... A 385-volt metal oxide varistor A varistor is an electronic component with a significant non-ohmic current-voltage characteristic. ... Zinc oxide is a chemical compound with formula ZnO. It is nearly insoluble in water but soluble in acids or alkalis. ...


Silicon carbide is used for blue LEDs, ultrafast, high-voltage Schottky diodes, MOSFETs and high temperature thyristors for high power switching. A famous paper by Jayan Baliga[2] shows enormous potential of SiC as a power device material. However, some problems with the interface of SiC with silicon dioxide has hampered the development of SiC based power MOSFET and IGBTs. Extensive research is going on to solve the problem. Due to its high thermal conductivity, SiC is also used as substrate for other semiconductor materials such as gallium nitride.[3] Due to its wide band gap, SiC-based parts are capable of operating at high temperature (over 350 °C), which together with good thermal conductivity of SiC reduces problems with cooling of power parts. They also possess increased tolerance to radiation damage, making it a material desired for defense and aerospace applications. Its main competitor is gallium nitride. Although diamond has an even higher band gap, SiC-based devices are easier to manufacture due to the fact that it is more convenient to grow an insulating layer of silicon dioxide on the surface of a silicon carbide wafer than it is with diamond. “LED” redirects here. ... Schottky diode schematic symbol The Schottky diode (named after German physicist Walter H. Schottky; also known as hot carrier diode) is a semiconductor diode with a low forward voltage drop and a very fast switching action. ... Large power N-channel field effect transistor The field-effect transistor (FET) is a transistor that relies on an electric field to control the shape and hence the conductivity of a channel in a semiconductor material. ... The thyristor is a solid-state semiconductor device similar to a diode, with an extra terminal which is used to turn it on. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... Gallium nitride (GaN) is a wide bandgap semiconductor material used in optoelectronic, high-power and high-frequency devices. ... This article or section does not adequately cite its references or sources. ... In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... Microelectronics designed for environments with high levels of ionizing radiation have special design challenges. ... Gallium nitride (GaN) is a wide bandgap semiconductor material used in optoelectronic, high-power and high-frequency devices. ... This article is about the gemstone. ... R-phrases R42 R43 R49 S-phrases S22 S36 S37 S45 S53 Flash point non-flammable Supplementary data page Structure and properties n, εr, etc. ...


Pure SiC is a poor electrical conductor. Addition of suitable dopants significantly enhances its conductivity. Typically, such material has a negative temperature coefficient between room temperature and about 900 °C, and positive temperature coefficient at higher temperatures, making it suitable material for high temperature heating elements. In science and engineering, conductors, such as a electrical connector, are materials that readily conduct electric current through electrical conduction. ... A dopant, also called doping agent and dope, is an impurity element added to a semiconductor lattice in low concentrations in order to alter the optical/electrical properties of the semiconductor. ... Positive Temperature Coefficient (PTC) referers to materials that when temperature is raised, the electrical resistance increases sharply. ... A heating element converts electricity into heat through the process of Joule heating. ...


Silicon carbide is also used as an ultraviolet detector. Nikola Tesla, around the turn of the 20th century, performed a variety of experiments with carborundum. Electroluminescence of silicon carbide was observed by Captain Henry Joseph Round in 1907 and by O. V. Losev in the Soviet Union in 1923.[4] For other uses, see Ultraviolet (disambiguation). ... Nikola Tesla (1856-1943)[1] was a world-renowned Serbian inventor, physicist, mechanical engineer and electrical engineer. ... Animation of LCD, both unlit and with electroluminiscent backlight switched on Electroluminescence (EL) is an optical phenomenon and electrical phenomenon where a material emits light in response to an electric current passed through it, or to a strong electric field. ... Captain Henry Joseph Round (2 June 1881, Kingswinford, Staffordshire, England–17 August 1966, Bognor Regis) was one of the early pioneers of radio and received 117 patents. ... Year 1907 (MCMVII) was a common year starting on Tuesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Monday of the 13-day-slower Julian calendar). ... Oleg Vladimirovich Losev (Russian: Олег Владимирович Лосев) (10 May 1903 - 22 January 1942[1], [2]) was a scientist and inventor. ... Year 1923 (MCMXXIII) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar. ...


Structural material

In the 1980s and 1990s, silicon carbide was studied on several research programs for high-temperature gas turbines in the United States, Japan, and Europe. The components were intended to replace nickel superalloy turbine blades or nozzle vanes. However, none of these projects resulted in a production quantity, mainly because of its low impact resistance and its low fracture toughness. The 1980s refers to the years from 1980 to 1989. ... For the band, see 1990s (band). ... For other uses, see Europe (disambiguation). ... For other uses, see Nickel (disambiguation). ... A superalloy, or high-performance alloy, is an alloy able to withstand extreme temperatures that would destroy conventional metals like steel and aluminum. ... A Siemens steam turbine with the case opened. ... In materials science and metallurgy, toughness is the resistance to fracture of a material when stressed. ...


Astronomy

Silicon carbide's hardness and rigidity make it a desirable mirror material for astronomical work, although its properties also make manufacturing and designing such mirrors quite difficult. A mirror, reflecting a vase. ... For other uses, see Astronomy (disambiguation). ...


Silicon carbide may be a major component of the mantles of as-yet hypothetical carbon planets. Planets orbiting the pulsar PSR 1257+12 may be carbon planets A carbon planet, also referred to as a diamond planet or carbide planet is a theoretical type of terrestrial planet proposed by Marc Kuchner with internal layers of diamond many kilometres thick. ...


Grit

Silicon carbide is a popular product in modern lapidary due to the durablility and low cost of the material. It is also used in coarse to fine grit sandpapers and as a grip tape in skateboards. A lapidary (the word means concerned with stones) is an artisan who practices the craft of working, forming and finishing stone, mineral, gemstones, and other suitably durable materials (amber, shell, jet, pearl, copal, coral, horn and bone, glass and other synthetics) into functional and/or decorative, even wearable, items (e. ... Look up grit, GRIT, grits, GRITS in Wiktionary, the free dictionary. ... sheets of sandpaper Sandpaper is a form of paper where an abrasive material has been fixed to its surface; it is part of the coated abrasives family of abrasive products. ... A standard skateboard An old-school skateboard A skateboard is a four wheeled platform used for the activity of skateboarding. ...


Disc brake

Silicon-infiltrated carbon-carbon composite is used for high performance brake discs as it is able to withstand extreme temperatures. The silicon reacts with the graphite in the carbon-carbon composite to become silicon carbide. These discs are used on some sports cars, including the Porsche Carrera GT. Reinforced Carbon-Carbon (RCC) consists of carbon fiber reinforcement in a matrix of graphite, often with a silicon carbide coating to prevent oxidation. ... It has been suggested that this article or section be merged into Vehicle brake. ... The Porsche Carrera GT was a supercar manufactured by Porsche in Germany. ...


Clutch

The Porsche Carrera GT has two plates made of silicon carbide as well.


Diesel particulate filter

Silicon carbide is used in a sintered form for diesel particulate filters. Sintering is a method for making objects from powder, increasing the adhesion between particles as they are heated. ... A diesel particulate filter (top left) in a Peugeot A diesel particulate filter, sometimes called a DPF, is device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine, most of which are rated at 85% efficiency, but often attaining efficiencies of over 90...


Thin filament pyrometry

Silicon carbide fibers are used to measure gas temperatures in a diagnostic technique called thin filament pyrometry. TFP image in diluted methane flame. ...


Ceramic membrane

Silicon carbide is used for producing ceramic membranes for industrial processes, yielding high fluxes due to the sintering process.


Cutting tools

In 1982 at the Oak Ridge National Laboratories, George Wei, Terry Tiegs, and Paul Becher discovered a composite of aluminium oxide and silicon carbide whiskers. This material proved to be exceptionally strong. Development of this laboratory-produced composite to a commercial product took only three years. In 1985, the first commercial cutting tools made from this alumina and silicon carbide whisker-reinforced composite were introduced by the Advanced Composite Materials Corporation (ACMC) and Greenleaf Corporation. A combination of federal, state and private funds is providing $300 million for the construction of 13 facilities on ORNLs new main campus. ... Aluminium oxide is an amphoteric oxide of aluminium with the chemical formula Al2O3. ... Metal whiskers are a crystalline metallurgical phenomenon whereby metal grows tiny, filiform hairs. ...


Heating element

References to silicon carbide heating elements exist from the early 20th century when they were produced by Acheson's Carborundum Co. in the U.S. and EKL in Berlin. Silicon carbide offered increased operating temperatures compared with metallic heaters, although the operating temperature was limited initially by the water-cooled terminals, which brought the electric current to the silicon carbide hot zone. The terminals were not attached to the hot zone, but were held in place by weights, or springs. Operating temperature and efficiency was later increased by the use of separate low resistance silicon carbide "cold ends", usually of a larger diameter than the hot zone, but still held in place only by mechanical pressure. The development of reaction-bonding techniques led to the introduction of jointed elements. Initially, these featured larger diameter cold ends, but by the 1940s, equal diameter elements were being produced. From the 1960s onwards, one-piece elements were produced, with cold ends created by filling the pore volume with a silicon alloy. Another one-piece technique is to cut a spiral slot in a homogeneous tube where the hot section is desired. Further developments have included the production of multi-leg elements, where two or more legs are joined to a common bridge, and the production of high density, reaction-bonded elements, which provide additional resistance to oxidation and chemical attack. Silicon carbide elements are used today in the melting of non-ferrous metals and glasses, heat treatment of metals, float glass production, production of ceramics and electronics components, etc. A heating element converts electricity into heat through the process of Joule heating. ... The most fundamental reactions in chemistry are the redox processes. ... Heat treatment is a method used to alter the physical, and sometimes chemical, properties of a material. ... Float glass is made by melting raw materilas consisting of sand, limestone, soda ash, dolomite, iron oxide and salt cake. ...


Nuclear Fuel

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. Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... Nuclear Fuel Process A graph comparing nucleon number against binding energy Nuclear fuel is any material that can be consumed to derive nuclear energy, by analogy to chemical fuel that is burned to derive energy. ... The High Temperature Gas-cooled Reactor or HTGR is a gas cooled reacter that is fueled with a mixture of graphite and spherical fuel particles. ... Very high temperature reactor scheme. ... Graphite Pebble for Reactor The pebble bed reactor (PBR) or pebble bed modular reactor (PBMR) is an advanced nuclear reactor design. ...


Jewel

As a jewel used in jewelry, silicon carbide is called Moissanite for the jewel's discoverer Dr. Henri Moissan[5]. Moissanite is somewhat similar to diamond in several important respects: it is transparent and hard (9, although a patent states 8.5-9.0,[6] -note on the Mohs scale compared to 10 for diamond), with a refractive index between 2.65 and 2.69 (compared to 2.42 for diamond). Moissanite is somewhat harder than common cubic zirconia. Unlike diamond, Moissanite is strongly birefringent. This quality is desirable in some optical applications, but not in gemstones. For this reason, Moissanite jewels are cut along the optic axis of the crystal to minimize birefringent effects. It is lighter (density 3.22 vs. 3.56), and much more resistant to heat. This results in a stone of higher lustre, sharper facets and good resilience. Loose moissanite stones may be placed directly into ring moulds; unlike diamond, which burns at 800 °C, moissanite remains undamaged by temperatures up to twice the 900 °C melting point of 18k gold. For other uses, see Gemstone (disambiguation). ... For the Korean music group, see Jewelry (group). ... Ferdinand Frederick Henri Moissan (September 28, 1852 – February 20, 1907) was a French chemist who won the 1906 Nobel Prize in Chemistry for his work in isolating fluorine from its compounds. ... This article is about the gemstone. ... This article or section does not cite any references or sources. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... A round brilliant-cut cubic zirconia Cubic zirconia (or CZ), the cubic crystalline form of zirconium dioxide (ZrO2), is a mineral that is widely synthesized for use as a diamond simulant. ... A calcite crystal laid upon a paper with some letters showing the double refraction Birefringence, or double refraction, is the division of a ray of light into two rays (the ordinary ray and the extraordinary ray) when it passes through certain types of material, such as calcite crystals, depending on... The term optical axis has the following meanings: 1. ... Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock or mineral. ... Carat is a measure of the purity of gold and platinum alloys. ... GOLD refers to one of the following: GOLD (IEEE) is an IEEE program designed to garner more student members at the university level (Graduates of the Last Decade). ...


In 1998, Charles & Colvard introduced jewel-quality synthetic silicon carbide to the market under the name "moissanite". This gemstone possesses superior fire and brilliance to diamonds. Upon introduction, some jewelers misidentified moissanite as diamond. Moissanite's thermal conductivity is very close to that of diamond, rendering useless the older thermal testers that they relied upon. Moissanite has a slightly higher index of refraction (brilliance) and much greater dispersion (fire) than diamond, as it shows many more "flashes" of color than a diamond. Unlike cubic zirconia and other diamond simulants, moissanite does not cloud over time, and is extremely durable. In physics, thermal conductivity, k, is the intensive property of a material that indicates its ability to conduct heat. ... The refractive index of a material is the factor by which electromagnetic radiation is slowed down (relative to vacuum) when it travels inside the material. ... Dispersion of a light beam in a prism. ...


Once its properties are known, moissanite is easy to distinguish from diamond, as it is doubly refractive and has a very slight green, yellow, or gray fluorescence under ultraviolet light. Because the brilliance of the moissanite helps to cancel the perceived color, cuts with higher brilliance tend to have a much "whiter appearance" (i.e., round brilliant, square brilliant, and cushion cut) versus cuts that have a lower refractive index such as the marquise, radiant and especially the pear-shaped cut. The color is often defined as "near colorless" which on the diamond color scale ranges from G through J. A calcite crystal laid upon a paper with some letters showing the double refraction Birefringence, or double refraction, is the decomposition of a ray of light into two rays (the ordinary ray and the extraordinary ray) when it passes through certain types of material, such as calcite crystals, depending on...


Charles & Colvard markets moissanite primarily to self-purchasing women. However, moissanite engagement rings, eternity bands and circle pendants have become popular among value-conscious consumers. For example, a 1-carat (200 mg) moissanite gem sells for about $500 (2007 USD), while a diamond of similar size and color typically sells for $4500 or more. Moissanite jewelry is sold at a wide variety of internet and retail outlets.


Steel

Piece of silicon carbide used in steel making

Silicon carbide dissolved in a basic oxygen furnace used for making steel acts as a fuel and provides energy which increases the scrap to hot metal ratio.[7] It can also be used to raise tap temperatures and adjust the carbon content. Image File history File links Download high resolution version (1500x1125, 287 KB) Summary A chunk of silicon carbide acquired from Carbo-Sil by Steve Karg. ... Image File history File links Download high resolution version (1500x1125, 287 KB) Summary A chunk of silicon carbide acquired from Carbo-Sil by Steve Karg. ... The basic oxygen furnace is the place within a foundry where molten iron from the blast furnace is changed into liquid steel. ... For other uses, see Steel (disambiguation). ... For other uses, see Fuel (disambiguation). ...


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.[8] According to Miller and Company,[9] it costs less than ferrosilicon and carbon combination, produces cleaner steel due to low level of trace elements, it has a low gas content, it does not lower the temperature of steel, and it has an abundant world wide supply. The silicon carbide used as a steel additive or fuel comes as a granular product in either bulk and bags. LADLE ... A deoxidizer is a chemical used in a reaction or process to remove oxygen. ... Not to be confused with Silicone. ... For other uses, see Carbon (disambiguation). ... LADLE ... A furnace is a device for heating air or any other fluid. ... Slag is also an early play by David Hare. ... Ferrosilicon, or ferrosilicium, is a ferroalloy an alloy of iron and silicon with between 15 and 90% silicon. ... For other uses, see Carbon (disambiguation). ... Microminerals (also known as trace elements) are micronutrients that are chemical elements. ...


50% and 65% silicon carbide are used in the steel industry for processing steel and iron scrap. Typically supplied as blocks and made from silicon carbide crucible scrap, it helps extend the hot metal supply and raises the tap temperature.[10] The blocks are typically made using an automated concrete block making machine, and utilize water and limestone cement as a binder. Steel framework Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... A stack of rectangular cinder blocks A cinder block (also mistakenly called a concrete block), breeze block, or Concrete Masonry Unit (CMU), is a rectangular block or brick used in construction. ... A stack of rectangular cinder blocks A cinder block (also mistakenly called a concrete block), breeze block, or Concrete Masonry Unit (CMU), is a rectangular block or brick used in construction. ... The Breezeblock is also a radio show on BBC Radio 1. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Limestone (disambiguation). ... In the most general sense of the word, cement is a binder, a substance which sets and hardens independently, and can bind other materials together. ...


Armour

Like some other hard ceramics (namely alumina and boron carbide), silicon carbide is used in composite armour (eg. Chobham armour), and in ceramic plates in bulletproof vests. Aluminium oxide (or aluminum oxide) (Al2O3) is a chemical compound of aluminium and oxygen. ... Boron carbide (chemical formula B4C) is an extremely hard ceramic material used in tank armor, bulletproof vests, and numerous industrial applications. ... Composite armour is a type of vehicle armour consisting of layers of different material such as metals, plastics, ceramics or air. ... Chobham armour is a composite armour developed in the 1960s at the British tank research centre on Chobham Common. ... It has been suggested that Small-arms protective insert be merged into this article or section. ... This article or section does not adequately cite its references or sources. ...


Catalyst Support

The natural resistance to oxidation exhibited by silicon carbide, as well as the discovery of new ways to synthesize the higher surface area beta form, has led to significant interest in its use as a heterogeneous catalyst support. The beta cubic form has already been employed for several years as a catalyst support for the oxidation of C4 hydrocarbons, such as n-butane, to maleic anhydride.


In popular culture

  • In Edgar Rice Burroughs' Barsoom series, "carborundum" is used as building material for city walls.
  • In 2001: A Space Odyssey and the related series of books and movies (by Arthur C. Clarke and Stanley Kubrick, among others) the monoliths (or at least their exteriors) were made of silicon carbide
  • In the Discworld novel Monstrous Regiment: Carborundum is the name of the Troll that enlists.
  • In the movie Snatch, a pawn shop employee (Sol) determines a diamond is actually Moissanite, much to the dismay of the thief (Bad Boy Lincoln) who stole the ring.
  • The name of the material is part of the pun "Illegitimi non carborundum" (Dog Latin for "don't let the bastards grind you down"), which figures into a football fight song of Harvard University among other things.
  • In the BBC television show Top Gear, host Jeremy Clarkson expresses excitement over the mere mention of silicon carbide used in the brakes and clutch of the Porsche Carrera GT.
  • Silicon carbide is the material used for the National Design Awards trophy, awarded by the Cooper-Hewitt National, Design Museum designed by William Drenttel and Jessica Helfand and manufactured by Norton Electronics.

Edgar Rice Burroughs Edgar Rice Burroughs (September 1, 1875 – March 19, 1950) was an American author, best known for his creation of the jungle hero Tarzan, although he also produced works in many genres. ... A Princess of Mars by Edgar Rice Burroughs, McClurg, 1917 Barsoom is a fictional version of the planet Mars invented by author Edgar Rice Burroughs for a series of action adventure stories. ... Sir Arthur Charles Clarke, CBE (born 16 December 1917) is a British science-fiction author and inventor, most famous for his novel 2001: A Space Odyssey, and for collaborating with director Stanley Kubrick on the film of the same name. ... “Kubrick” redirects here. ... A monolith is a geological or technological feature such as a mountain, consisting of a single massive stone or rock. ... Cover of an early edition of The Colour of Magic; art by Josh Kirby Discworld is a comedic fantasy book series by the British author Terry Pratchett set on the Discworld, a flat world balanced on the backs of four elephants which are in turn standing on the back of... Monstrous Regiment is the 31st novel in Terry Pratchetts Discworld series. ... Snatch is a 2000 film by British writer-director Guy Ritchie. ... Illegitimi non carborundum is a mock-Latin aphorism jokingly taken to mean dont let the bastards grind you down. There are many variants of the phrase, such as Non illegitimis carborundum. ... The phrase Dog Latin refers to the creation of a phrase or jargon in imitation of Latin, often by directly translating English words (or those of other European languages) into Latin without conjugation or declension. ... Harvard University (incorporated as The President and Fellows of Harvard College) is a private university in Cambridge, Massachusetts, USA and a member of the Ivy League. ... The current format of Top Gear is a BAFTA[1] and Emmy Award-winning BBC television series about motor vehicles, mainly cars. ... Jeremy Charles Robert Clarkson (born 11 April 1960) is an English broadcaster and writer who specialises in motoring. ... The National Design Awards, founded in 1997, is funded and awarded by Cooper-Hewitt, National Design Museum. ... William Drenttel is a graphic designer, editor and currently a partner in Winterhouse Studios and president emeritus of the American Institute of Graphic Arts (AIGA). ... Jessica Helfand is an author, columnist and lecturer on graphic design. ...

Patents and trademarks

Edward Goodrich Acheson (1856–1931) patented the method for making silicon carbide powder on February 28, 1893. On May 19, 1896, he was also issued a patent for an electrical furnace used to produce silicon carbide.[11] Carborundum is a trademark of Saint-Gobain Abrasives. February 28 is the 59th day of the year in the Gregorian calendar. ... Year 1893 (MDCCCXCIII) was a common year starting on Sunday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Tuesday of the 12-day slower Julian calendar). ... is the 139th day of the year (140th in leap years) in the Gregorian calendar. ... Year 1896 (MDCCCXCVI) was a leap year starting on Wednesday (link will display calendar). ... St. ...


See also

Due to its low cost and close visual likeness to diamond, cubic zirconia has remained the most gemologically and economically important diamond simulant since 1976. ... Illegitimi non carborundum is a mock-Latin aphorism jokingly taken to mean dont let the bastards grind you down. There are many variants of the phrase, such as Non illegitimis carborundum. ... For other uses, see Latin (disambiguation). ... In linguistics, a gerund is a non-finite verb form that exists in many languages. ...

References

  1. ^ http://img.chem.ucl.ac.uk/www/kelly/history.htm
  2. ^ Comparison of 6H-SiC, 3C-SiC, and Si for power devices, Bhatnagar, M., Baliga, B.J., IEEE Transactions on Electron Devices, March 1993
  3. ^ http://www.qinetiq.com/home/commercial/information_communication_and_electronics/Electronics/optronics/quantum_electronics.html
  4. ^ http://www.indiana.edu/~hightech/fpd/papers/ELDs.html
  5. ^ Moissanite Education
  6. ^ Patent #5,762,896 Espacenet record
  7. ^ http://www.millerandco.com/products/briquettes_steel/
  8. ^ http://www.millerandco.com/products/briquettes_steel/specifications/briq90.htm
  9. ^ Miller and Company
  10. ^ http://www.millerandco.com/products/briquettes_steel/specifications/briq65.htm
  11. ^ U.S. Patent 492,767  -- Production of artificial crystalline carbonaceous material

References

^  Most in the jewelry industry may not recognize the 1/4 fractional intervals on the Mohs scale (a relative scale), and it is technically not correct since the Mohs scale only contains whole and half numbers. But the issuers of the patent use it in showing exactly where certain minerals are in relation to each other. On the original Mohs scale diamond was listed as a 10 and sapphire is listed as a 9. On an absolute scale, a diamonds hardness is between 5700–10400 on the Knoop scale, while a sapphire's hardness is 2000. The Knoop hardness of moissanite is 3000. This puts the Mohs hardness of moissanite around 8.5–9.25—as stated here, 9 1/4 may not be recognized, but 8.5–9.25 is the number used in the patents.


External links


  Results from FactBites:
 
Method of coating carbon filaments with silicon carbide - Patent 4131697 (1077 words)
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.
LBNL MSD - De Jonghe/Silicon Carbide Ceramic (375 words)
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.
  More results at FactBites »

 
 

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