409-21-2

Basic information

• Product Name: Silicon carbide
• Synonyms: Silicon carbide -400 Mesh particle size, >=97.5%;Silicon carbide nanowhiskers;Silicon carbide nanofiber, D = 20, 98% trace metals basis;Silicon carbide nanopowder, ;CARBORUNDUM 0,037 MM;CARBORUNDUM 0,500 MM;CARBORUNDUM 1,190 MM;CARBORUNDUM 1,680 MM
• CAS NO: 409-21-2
• Molecular Formula: CSi
• Molecular Weight: 40.1
• EINECS: 206-991-8
• Product Categories: Inorganics;Carbides;Ceramics;Metal and Ceramic Science;CarbidesMaterials Science;14: Si;Nanomaterials;Nanoparticles: Oxides, Nitrides, and Other CeramicsNanomaterials;Nanopowders and Nanoparticle Dispersions;metal borides and carbides
• Mol File: 409-21-2.mol
• Article Data: 0

Chemical Properties

• Melting Point: 2700 °C(lit.)
• Appearance: Green/nanopowder
• Density: 3.22 g/mL at 25 °C(lit.)
• Refractive Index: 2.6500
• Solubility: Soluble in molten sodium hydroxide, potassium hydroxide and in m
• Water Solubility: Soluble in molten alkalis (NaOH, KOH) and molten iron. Insoluble in water.
• Stability: Stability
• Merck: 14,8492
• CAS DataBase Reference: Silicon carbide(CAS DataBase Reference)
• NIST Chemistry Reference: Silicon carbide(409-21-2)
• EPA Substance Registry System: Silicon carbide(409-21-2)

Safety Data

• Hazard Codes: Xi
• Statements: 36/37/38
• Safety Statements: 26-36
• WGK Germany: 3
• RTECS: VW0450000
• TSCA: Yes
• Hazardous Substances Data: 409-21-2(Hazardous Substances Data)

Usage

Uses

Different sources of media describe the Uses of 409-21-2 differently. You can refer to the following data:
1. Silicon carbide (SiC), nearly as hard as diamonds, is used as an abrasive in grinding wheels and metal-cutting tools, for lining furnaces, and as a refractory in producing nonferrous metals.
2. ▼▲ 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 Alchemy blast furnace brick Raw material/anti high-temperature property Graphite electrode production Coating component/increase the coating capacity of rapid temperature change Others Thin filament pyrometry Filament material/anti high-temperature property Nuclear fuel particles Ingredient/anti high-temperature property Nuclear fuel cladding Synthetic moissanite gemstone Raw material/similar to diamond in several important respects Steel production Additional fuel/allows the furnace to process more scrap with the same charge of hot metal Catalyst support Support material/large surface area Carborundum printmaking Paste material for ink plate
3. 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.
4. Manufacture of abrasives and refractories, brake linings, heating elements, and thermistors.

Description

Silicon carbide is a hard covalently bonded material predominantly produced by the carbothermal reduction of silica. Silicon carbide is made by heating silica sand and petroleum coke packed around electrodes in an electric resistance furnace to above 2200°C. Depending on the exact reaction conditions the resulting silicon carbide is either a fine powder or a bonded mass that requires crushing and milling to produce a usable feedstock. This material is very resistant to abrasion and to corrosion with a molten slag. It also has excellent resistance to thermal spalling. However as it is a carbide, it will oxidise readily, silicon carbide has a fairly high conductivity. Several hundred structures of silicon carbide (polytypes) have been identified which have different stacking arrangements for the silicon and carbon atoms. The simplest structure is a diamond structure which is designated /3-SiC. Other structures are either hexagonal or rhombic and are referred to as a-SiC.

Chemical Properties

Different sources of media describe the Chemical Properties of 409-21-2 differently. You can refer to the following data:
1. Silicon carbide is a yellow to green to bluishblack, iridescent crystalline substance. Colorless when pure.
2. light grey powder

Physical properties

the 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. In addition, the high hardness, corrosion resistance and stiffness lead to a wide range of applications where wear and corrosion resistance are primary performance requirements. 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.

Characteristics

Silicon carbide is a premium-priced unit which is employed in lining work for its uniformity, abrasion resistance and dimensional stability. It is resistant to most organics, inorganic acids, alkalis and salts in a variety of concentrations except to hydrofluoric acid and acid fluorides. The permeable units have the lowest resistance.

Production Methods

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.

Preparation

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.

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.

General Description

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.

Reactivity Profile

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

Nonflammable

Industrial uses

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.

Safety Profile

Suspected carcinogen with experimental neoplastigenic data. A nuisance dust.

Potential Exposure

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.

Incompatibilities

Dust may form explosive mixture with air. Sublimes with decomposition @ 2700C.

Waste Disposal

Landfill

References

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.http://www.lookchem.com/productchemicalpropertiescb2431905.htm

InChI:InChI=1/C.Si/q+4;-4