Struktura in uporaba silicijevega karbida

Silicon carbide, or SiC, is an extremely strong and durable material with some unique electrical properties.

Crystalline carbon can be found crystallizing into densely packed structures that are covalently bonded together. Its atoms form two primary coordination tetrahedra with four carbon and four silicon atoms in each corner that link through their corners to form polytype structures called polytypes.

Physical Properties

Silicon carbide is an extremely hard material with a Mohs hardness rating between 9 and 10, falling somewhere in between alumina and diamond. Silicon carbide finds extensive use as an abrasive material in modern lapidary, in grinding and machining operations, as refractory lining for industrial furnaces, cutting tools, wear-resistant parts of pumps and rocket motors as well as wear-resistant grip tape on skateboards as well as carborundum printmaking — the process of applying carborundum grit to an aluminum plate and then printing off onto paper using rolling-bed presses (Mountain).

Synthetic polycarbonates can be produced synthetically using either reaction bonding or sintering processes, with the latter enhanced through addition of 0.5% carbon or 0.5% boron as a sintering aid, to prevent surface diffusion and modify grain boundary energy (Mountain).

SiC is an impressive industrial ceramic with diverse mechanical properties that makes it invaluable in various industrial settings. With high thermal conductivity and low thermal expansion rates, its use in power electronics for terrestrial electric vehicle drive systems has become more prevalent than ever. Furthermore, SiC’s electrical characteristics could also replace traditional silicon semiconductors in higher voltage applications like traction inverters for electric vehicles and DC/DC converters for charging stations.

Chemical Properties

Silicon carbide can be doped with nitrogen and phosphorus to form n-type semiconductors, while beryllium, boron, aluminum, and gallium can be doped into it to make p-type ones. Due to its close-packed and symmetrical structure, silicon carbide provides an ideal platform for doping.

Refractory material is hard, brittle and thermally conductive. It can withstand high temperatures and voltages while its low thermal expansion coefficient offers advantages when used for applications subject to temperature variations.

Though natural moissanite (Csi3SiO6) can be found in meteorites and kimberlite, most silicon carbide sold today is synthetic. It comes in many forms from green to black crystalline grains to six inch SiC wafers used for power electronics applications, and is chemically inert as it resists corrosion from organic acids and alkalis, with exception of hydrofluoric and sulphuric acids; insoluble in water or other solvents yet soluble in molten alkalis such as NaOH or KOH.

Electrical Properties

Silicon carbide (SiC) is a semiconductor material, situated between metals (which conduct electricity) and insulators (which do not). SiC’s electrical properties depend on temperature and impurities in its composition: at low temperatures it acts like an insulator; while at higher temperatures its conductivity becomes noticeable. SiC conductivity can further be improved by adding aluminum, boron or gallium impurities which increase free charge carriers and convert SiC into P-type semiconductor.

Clay’s combination of physical and chemical properties make it an attractive material in various industries, from ceramic plates that increase abrasion resistance and brake strength, to its high thermal conductivity and low coefficient of expansion that allow it to be used in high temperature applications.

Additionally, its unique bandgap allows it to operate at higher voltages and frequencies than traditional silicon-based electronics, making it the perfect material for power devices such as diodes, transistors, and thyristors.

Thermal Properties

Silicon carbide (SiC) is an inorganic ceramic with superior thermal properties, making it suitable for many different applications. Silicon carbide finds use in applications ranging from wear-resistant parts and abrasives due to its hardness; in refractories and ceramics due to its resistance to heat and low thermal expansion; as well as electronics where its ability to conduct electricity under extreme temperatures.

SiC is an effective thermal conductor due to its diamond cubic crystal structure with half of the atoms replaced with silicon, providing superior thermal conductivity. SiC features an efficient bandgap which enables electrons to easily move between its valence and conduction bands compared with insulators which require excessive amounts of energy for electrons to cross this gap between their bands.

SiC’s crystal structure can take various forms, known as polytypes. Each polytype consists of layers stacked in specific stacking sequences that result in unique atomic arrangements – this gives SiC an extremely high specific heat and low thermal expansion coefficient.