What Is Silicon Carbide Composition?

Silicon carbide (SiC) is an extremely hard and sturdy chemical compound composed of silicon and carbon that features wide band gap semiconductor properties for use in high temperature and voltage electronic devices.

SiC is found naturally as a mineral known as moissanite and was first mass-produced as an abrasive in 1893. Since then it has become an extremely durable ceramic used in numerous applications from automotive brakes and clutches to bulletproof vests.

Характеристики

Silicon carbide is an inert compound consisting of silicon and carbon that has the chemical property of being inert and hard. When doped with nitrogen, phosphorus or gallium doping agents to form semiconductors. When crystallized it forms close-packed structures where each atom forms four carbon/silicon tetrahedra that form covalent bonds with one another forming four cubic structures of covalently bound silicon/carbon tetrahedrons covalently connected by covalent bonds.

SiC is an extremely hard and durable material with excellent electrical properties that make it suitable for components operating at high temperatures and frequencies without compromising reliability, such as transistors and Schottky diodes.

Edward Acheson produced artificial silicon carbide for the first time in 1891 by accident when heating carbon and silica mixture in an electric furnace, producing black diamond-simulating crystals resembling diamond. Later observed naturally at Canyon Diablo meteorite site in Arizona by Henri Moissan who named this substance moissanite.

Industrially, silicon carbide can be created either through reaction bonding or sintering processes; both methods have significant influences on its final microstructure. Reaction bonded SiC can be created by infiltrating compacts composed of silicon carbide and carbon with liquid silicon; this causes more SiC to bond to original particles through chemical reaction. Sintering involves pressing powdered SiC into ingots until an unreacted layer forms between two reacted layers; then pressing them again creates layers a-SiC and b-SiC with unreacted layers between them resulting from pressing powdered SiC ingots; this creates layers a-SiC and b-SiC with unreacted layers between them with an unreacted layer in between them, as opposed to reaction bonded SiC, with unreacted layers between two infill-bonding methods producing SiC ingots formed from pressing powdered SiC ingots from press pressing powdered SiC into ingots created via pressing powdered SiC into ingots where layers formed of both layers (a-SiC and b-SiC with unreacted layers between). Sintering involves pressing powdered SiC into ingots where layers formed (a-SiC and an unreacted layer formed between).

Health and safety risks caused by dust and fibers generated during processing are the primary concerns with hard materials such as graphite. They may irritate eyes and skin, cause respiratory conditions like lung fibrosis, or contribute to cancerous growths.

Properties

Silicon carbide in its pure form boasts excellent chemical and heat resistance, making it suitable for grinding hard metals such as those found in modern metalworking operations. Due to its highly abrasive surface, silicon carbide also serves as a popular abrasive used in modern lapidary work as it is both durable and relatively affordable. Silicon carbide also finds use as heating elements in industrial furnaces as well as wear-resistant parts used on machinery like crushers and pumps as well as semiconductor substrates for light emitting diodes (LEDs).

Silicon carbide can be formed into different polymorphs by controlling its temperature of reaction and process of formation, with alpha silicon carbide (a-SiC), featuring hexagonal crystal structure similar to Wurtzite. Meanwhile beta silicon carbide (b-SiC) features zinc blende crystal structure resembling diamond. Finally tetrahedral silicon carbide (TiC), having high voltage resistance but only being made in small quantities is considered the most challenging of them all.

Pure SiC is an opaque yellow-to-green to bluish-black crystal with an average density of 3.21 g/cm3 that melts at 2700 degC, has insoluble water solubility, yet dissolves with alkalies like NaOH or KOH in solution. When fused to silicon it forms carbide glass while when vaporized into single crystal boules can be formed for use in electronic devices.

Додатки

Silicon carbide is an exceptionally strong, corrosion-resistant and hard material with Mohs hardness rating of 9. Its scratch resistance makes it very difficult to scratch or break, making it perfect for high voltage applications such as automotive brakes. Silicon carbide’s wide band gap semiconductor characteristics also reduce energy requirements for shifting electrons into its conduction band (three times lower than silicon). This makes silicon carbide an excellent candidate for high voltage applications.

Carbon carbide can be made synthetically by reacting carbon with silica sand in an electric graphite furnace at temperatures between 1,600 to 2,500 degC, first created artificially by Edward Acheson in 1891 for industrial abrasive purposes. His work inspired Henri Moisan in France to synthesize silicon carbide by mixing quartz with carbon, giving rise to moissanite which now commonly used as jewelry.

Silicon carbide, as a refractory material, has numerous applications that span from making cutting tools and abrasives, structural materials (bulletproof vests and composite armor), automobile parts (brake disks) to wear resistant materials for pumps and rocket engines. Silicon carbide also finds use as light-emitting diodes and transistors because of its low thermal expansion rate, resistance to chemical reaction and ability to withstand high temperatures; its rigidity, hardness and high thermal conductivity make it an attractive mirror material choice for astronomical telescopes due to space conditions as well as radiation levels which could destroy other optical materials.

Виробництво

Silicon carbide manufacturing processes involve several steps designed to produce top-quality material. Raw materials must first undergo stringent purification processes that remove impurities; this allows manufacturers to better control composition of their final product.

After purification, silicon and carbon powders are combined in specific proportions to create the desired SiC composition. They are then formed into various forms such as chips or abrasive grains using various techniques such as pressing, extrusion and slip casting before being heated at high temperatures using sintering for further consolidation into more solid, dense and durable products with improved mechanical properties.

Silicon carbide products include ceramic bulletproof vests and automotive brakes and clutches made of silicon carbide; large single crystals of SiC can even be grown to make rare gems like moissanite.

SiC is an inorganic chemical compound, but it can be made to behave more like a semiconductor by adding impurities such as nitrogen or phosphorus that create n-type and p-type regions respectively. This allows SiC to conduct electricity according to temperature and intensity changes – making it perfect for power electronics applications.