Industry
Application
Role/benefit
Abrasive machining processes
Processing of glass, ceramic, stone, refractory, hard alloy, etc.
Abrasive and cutting tools/durability and low cost
Electronic
Light-emitting diodes
Component/electroluminescence property
Semiconductor devices
Component/has wide forbidden band (2.86 EV) and p and n two conductive types
Electric systems
Gapped SiC lightning arresters
Resistance/voltage-dependent property
Sic switches and SiC Schottky diodes
Raw material/anti high-temperature and high-voltage properties
Ceramics
Hard ceramics used for composite armor, bulletproof vests, etc.
Raw material/low density and high strength
Temperature ceramics
Raw material/has high intensity at High temperature
Astronomy
Astronomical telescopes
Mirror material/low thermal expansion coefficient, high hardness, rigidity and thermal conductivity
Aerospace
Gas filter and combustion chamber nozzle
Raw material/anti high-temperature property
Silicon carbide fibre
Reinforcing of metal,resin,alloy,glass,etc.
Reinforcing material/helps to improve all kinds of features
Heat shield material, high temperature filter cloth and conveyor belt
Raw material/anti high-temperature property
Automobile
Brake discs
Ingredient/helps to increase temperature resistance
Sintered form for diesel particulate filters
Ingredient/anti high-temperature property
Oil additive
Helps to educe friction, emissions, and harmonics
Carbon
Graphene production
Raw material
Manufacture of biochar
Coating material/helps to improve the Hardness, strength and wear resistance
Verwenden
Silicon carbide is widely used as an abrasive in grinding and cutting glasses; in polishing glass and sharpening stones. It is used in the manufacture of porcelain, refractory brick, furnace linings, and emery paper. The compound also is used in semiconductor technology.
Definition
Bluish-black, iridescent crystals. Insoluble in water and alcohol; soluble in fused alkalies and molten iron. Excellent thermal
conductivity, electrically conductive, resists oxida-
tion at high temperatures. Noncombustible, a nui-
sance particulate.
Vorbereitung Methode
SiC was synthesized at the end of the 18th century with the name carborundum, and it was used as abrasive. In 1920 in Russia, O.V. Losev discovered two types of SiC from electro-luminescence and named them Type I and Type II. The electro-luminescence of Type I is greenish blue colored and that of Type II changes from orange to violet via yellow and green as the voltage increases from 6 to 28 V. The pure crystal is nominally obtained as 6H (a-II) SiC and the crystals with impurity are obtained as 15R and 4H. a-SiC (6H, 15R) is mainly synthesized using the sublimation method by heating the mixture of coke and silica sands at 2000℃ in the electrical furnace. SiC is segregated by cooling after melting Si in the carbon crucible.
Vorbereitung Methode
Silicon carbide, also known by the trade name Carborundum,
has been manufactured and used as an abrasive material for
more than a century. It combines desirable properties of
hardness and thermal resistance. It is produced by heating
high-grade silica sand with finely ground carbon at 2400°C in
an electric furnace. In its powdered or granular form, it
has been used as the abrasive material in “paper and wheels.”
It is used as an abrasive in sandblasting and engraving. It has
been incorporated into ceramics and glass and especially into
refractory ceramic materials.
synthetische
Silicon carbide is prepared by fusing a mixture of silica (sand) and carbon (coke) with some salt and saw dust in an electric arc furnace at 3000°C.
SiO2(Sand)+3C(Coke)--(3000℃)--Sic+2CO
Salt and saw dust is added to infuse air into the product so that it can be broken into pieces easily. The product obtained is first washed with strong acid followed by strong base to remove basic and acidic impurities respectively. Finally, it is washed with water.
Reaktionen
SiC is formed by the reaction with C at high temperature. It is not etched by acid other than the mixture of hydrofluoric acid and nitric acid. It reacts with caustic solution generating H2 to produce alkali silicate. Good alloys can be formed at the composition ratio of 0%–100% with Ge. (Refer to Ge.)
Allgemeine Beschreibung
Yellow to green to bluish-black, iridescent crystals. Sublimes with decomposition at 2700°C. Density 3.21 g cm-3. Insoluble in water. Soluble in molten alkalis (NaOH, KOH) and molten iron.
Reaktivität anzeigen
Silicon carbide is non-combustible. Generally unreactive. Soluble in molten alkalis (NaOH, KOH) and in molten iron.
Hazard
Upper respiratory tract irritant. Probable
carcinogen.
Health Hazard
Silicon carbide, in certain forms,
may be a cause of pneumoconiosis in exposed
workers.
Silicon carbide has generally been considered
to be an inert dust with little adverse effect
on the lungs.
Flammability and Explosibility
Non flammable
Industrielle Verwendung
Silicon carbide is one of the very few totally man-made minerals used in refractory work. These are:
Oxide-bonded-(S102, A1201, Si02 or silicate glass), silicon oxynitride (Si2 ON2), silicon nitride (S13N4)
The first three of these four bonding systems result in a permeable product, and when failure occurs in such masonry systems due to chemical degradation, it is usually due to attack on the bond. Thus, permeable units (where the corrodent penetrates the mass) are far more rapidly damaged.
Self-bonded”—(silicon carbide to silicon carbide) impermeable ones, where the attack is limited to the surface.
The self-bonded product can be manufactured by either of two methods: reaction bonded or sintered. Both will produce an impermeable unit, and they have roughly comparable chemical resistances, but they do not have identical physical properties.
Sicherheitsprofil
Suspected carcinogen with experimental neoplastigenic data. A nuisance dust.
mögliche Exposition
A potential danger to those involved in the manufacture of silicon carbide abrasives, refractories, and semiconductors. Silicon carbide fibers are also produced in fibrous form as reinforcing fibers for composite materials.
Inkompatibilitäten
Dust may form explosive mixture with air. Sublimes with decomposition @ 2700C.
Waste disposal
Landfill
Einzelnachweise
1.https://en.wikipedia.org/wiki/Silicon_carbide#Uses
2.http://www.softschools.com/formulas/chemistry/silicon_carbide_uses_properties_structure_formula/282/
3.https://www.britannica.com/science/silicon-carbide
4.http://accuratus.com/silicar.html
5.https://www.intechopen.com/books/mostdownloaded/silicon-carbide-materials-processing-and-applications-in-electronic-devices
6.https://www.azom.com/article.aspx?ArticleID=3271
7.https://www.chemicalbook.com/productchemicalpropertiescb2431905.htm
