Difference between revisions of "Silicon carbide"
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Latest revision as of 23:32, 20 March 2020
Silicon carbide sample.
| IUPAC name
| Other names
|Molar mass||40.10 g/mol|
|Appearance||Black lustrous solid|
|Melting point||2,730 °C (4,950 °F; 3,000 K) (decomposes)|
|Solubility|| Reacts with molten alkali|
Insoluble in virtually all solvents
|Vapor pressure||~ 0 mmHg|
|Safety data sheet||ScienceLab|
| Silicon boride|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Silicon carbide, also known as carborundum is a compound of silicon and carbon with chemical formula SiC, mainly used as an abrasive. Silicon carbide occurs naturally as very rare mineral moissanite.
Silicon carbide resists the attack of many acids due to the formation of a thin layer of silicon dioxide, however, SiC will dissolve in molten alkali.
Silicon carbide is a black solid, with a density of 3.21 g/cm3, odorless, with a high melting point of 2,730 °C. It is extremely hard solid (9-9,5 on Mohs scale). SiC is insoluble in all solvents.
Silicon carbide is often present in abrasive materials and some semiconductors.
It can be also bought as moissanite which is highly attractive synthetic gem and is being used as a cheaper replacement for diamonds in jewellery.
Because of the rarity of natural moissanite, most silicon carbide is synthetic. However the preparation of SiC is too difficult for most amateur scientists. The simplest manufacturing process is to combine silica sand and carbon in an Acheson graphite electric resistance furnace at a high temperature, between 1,600 °C (2,910 °F) and 2,500 °C (4,530 °F). Fine SiO2 particles in plant material (e.g. rice husks) can be converted to SiC by heating in the excess carbon from the organic material. The silica fume, which is a byproduct of producing silicon metal and ferrosilicon alloys, also can be converted to SiC by heating with graphite at 1,500 °C (2,730 °F).
Silicon carbide is non-flammable and non-explosive. In bulk form is practically inert, while the powdered form is more hazardous:
Effects of Exposure: To the best of our knowledge the chemical, physical and toxicological properties of silicon carbide have not been thoroughly investigated and reported. Silicon carbide is a nuisance dust capable of producing nonprogressive pulmonary fibrosis. Silicon carbide implants have caused tumors in laboratory animals.
Acute Effects: Inhalation: May cause irritation. Ingestion: No acute health effects recorded. Skin: May cause abrasive irritation. Eye: May cause abrasive irritation.
Chronic Effects: Inhalation: May cause pneumoconiosis. No other chronic health effects recorded.
Target Organs: No target organs recorded. Medical Conditions Generally Aggravated by
Exposure: Pre-existing respiratory disorders.
Carcinogenicity: NTP: No IARC: No OSHA: No
Silicon carbide is very stable and doesn't require any special storage.
Silicon carbide isn't harmful to environment, so it's safe to dump it with normal trash or into the soil.