Silicon Carbide (SiC), commonly referred to as carborundum, is an extremely hard and durable ceramic material with low thermal expansion rates and great acid/lye resistance.
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Density
Silicon carbide (SiC) has a density of 3.21 g/cm3, much lower than silicon which has 2.33 g/cm3. As one of the strongest and hardest materials, SiC makes for ideal use in applications requiring high strength and abrasion resistance as well as its wide band gap and excellent thermal conductivity – perfect for power electronics that operate at higher temperatures and voltages.
Silicon carbide (SiC) is an alloy composed of silicon and carbon, known colloquially as “carborundum”. Naturally found within moissanite minerals, SiC has been mass produced since 1893 as powder and crystal for use as an abrasive. Applications include cutting and grinding tools, high pressure abrasion equipment such as crushers, limited thermal expansion and corrosion resistance and limited thermal expansion as refractory material in furnaces/kilns as well as blasting/lapping applications.
Silicon carbide’s key attributes go far beyond its low density and high strength; among these are its high melting point and excellent chemical stability – two characteristics that contribute significantly to its value. Furthermore, silicon carbide boasts exceptional resistance to corrosion as well as superior thermal conductivity; all qualities that help make this material such an invaluable commodity. When combined with metals such as aluminium to form stronger alloys.
Silicon carbide’s crystal structure is composed of hexagonal and rhombohedral layers with displaceable atoms of Si and C that are linked together by strong silicon-carbon bonds, while their dislocated positions lead to polytypism which has profound ramifications on physical properties of SiC.
Silicon carbide’s global market is expanding quickly due to an expanding power electronics sector and oil and gas applications where its properties offer advantages over more traditional materials. Furthermore, lightweight materials with increased strength, stiffness, and hardness have become more in demand among businesses seeking cost savings in production processes.
Specific Gravity
Silicon carbide boasts a specific gravity of 3.21 grams/cm3, making it one of the densest materials ever seen. Due to its high strength and wide band gap properties, silicon carbide can be used in cutting hard and soft materials alike, as well as being ideal for electronic applications.
SiC is noncombustible with low vapor pressure and dissolves easily in hot alkalis and iron solutions, as well as being nontoxic to animals and humans. Producing SiC naturally or synthetically is possible; natural SiC can be found in kimberlite or volcanic amphibolite while synthetic silicon carbide can be produced by reacting elemental silicon with carbon, while melting these two materials together in an electric furnace before grinding into particles and washing.
Safety and health should always come first when handling silicon carbide materials, since inhalation or swallowing of silicon carbide could result in lung damage – therefore proper safety precautions such as wearing protective eyewear or facemasks is paramount to ensure safe handling and wash the skin after working with this substance.
Silicon carbide is frequently utilized as a grinding medium, offering reliable grinding performance on hard materials like glass, ceramics and metals. Furthermore, this material offers exceptional fracture resistance at high temperatures while remaining heat resistant enough for cutting or lapping hard materials like marble, porcelain and carbide.
Silicon carbide possesses many beneficial physical properties, including corrosion and abrasion resistance. It boasts the same hardness as diamond, making it one of the hardest materials in existence. Furthermore, silicon carbide acts as an excellent electrical conductor with a wide band gap enabling it to operate at higher voltages.
Due to its excellent resistance against corrosion and oxidation, silicon carbide is frequently employed as an excellent raw material for producing fine ceramics. Furthermore, its excellent resistance makes it suitable for creating advanced refractory materials as well as advanced abrasive tools. Furthermore, silicon carbide boasts superior wear resistance than cast iron or rubber–making it an ideal material for manufacturing wear-resistant pipes, pumps and cyclones.
Топлопроводимост
Silicon carbide is an extremely hard, dense material with a high thermal conductivity due to the concentration of boron impurities, point defects and other factors – this high thermal conductivity being due to strong bonds between carbon atoms and silicon atoms that create the high thermal conductivity. These properties make silicon carbide suitable for hard machining applications due to its excellent shock resistance properties.
Silicon carbide’s chemical composition varies depending on its processing and sintering methods of production, including crystallographic density increases from sintering; aluminium and boron additives added during sintering increase sintered material’s strength while mechanical properties depend on factors like grain size/shape purity void orientation porosity etc.
Room-temperature strengths of pristine silicon carbide range between 4GPa and 4GPa when measured by their room-temperature strengths; however, CVD silicon carbide fibers decrease when heated beyond 800degC due to interfacial reactions between tungsten and the carbon-rich mantle, and carbon. Radial strength is lower than longitudinal tensile strength suggesting that surface defects drive most failure stress.
Silicon carbide’s thermal conductivity depends on its concentration of boron and crystallographic orientation, with higher-purity SiC having a value intermediate between pure diamond and copper in terms of thermal conductivity. When polycrystalline SiC is present, however, its thermal conductivity decreases due to defects like phase boundaries, solid solutions and lattice defects; various sintering additives and techniques may reduce their impact on thermal conductivity of silicon carbide.
Silicon carbide’s harmful effects depend on how and where it is produced and used, with some reactions including respiratory irritation, lung inflammation and stomach upset as a possible result of its production and usage. Furthermore, silicon carbide is considered by the International Agency for Research on Cancer as either probable (2a) or possible (2b). Furthermore, silicon carbide chemical has also been identified as potentially carcinogenic, leading to changes like fibrosis and inflammation within lung tissue.
Електрическа проводимост
Silicon carbide is an electrically semiconducting material, meaning its state can be altered when exposed to electric current or electromagnetic fields, changing from an insulator into conductor. This characteristic makes silicon carbide suitable for use in electronic devices that amplify, switch, convert, and regulate electrical energy flow – this includes diodes, transistors, thyristors and FETs/MOSFETs among many others. Silicon carbide’s semiconducting qualities combined with its hardness and wear resistance make it one of the world’s most versatile industrial materials.
Silicon carbide slices (slice) typically exhibit very low electrical conductivity on their own; however, their electrical conductivity can be greatly increased through adding conductive second phases such as carbon-rich polytype or nitride materials like yttrium oxide or zirconium dioxide that add to its electrical conductivity. A conductive layer usually forms at the interface between SiC crystals and such carbon-rich or nitride matrix matrixes.
Like thermal conductivity, electrical conductivity of slicing silicon carbides can be adjusted by selecting specific oxide additives, sintering atmosphere and processing techniques. For instance, adding yttrium oxide increases electrical conductivity significantly when sintered oxygen-free; similar inert gases such as nitrogen or helium can also help adjust this atmosphere during processing.
Mullite-bonded silicon carbide’s electrical conductivity can be adjusted in very wide ranges between 105 and 107 Ohm*cm at room temperature, enabling it to meet specific application-related conductivities even at high temperatures. This gives flexibility for designing circuits. Mullite-bonded silicon carbide is widely utilized for high temperature applications due to its excellent heat conductivity properties. However, for applications requiring higher performance levels, reaction bonding can be used to produce silicon carbide with an insulator-like crystalline structure called a-SiC or Wurtzite-SiC. This material is impervious to oxygen and resistant to internal oxidation at high temperatures, and typically prepared using chemical vapor infiltration (CVI) or polymer-impregnation-pyrolysis (PIP), two methods which are both more cost-effective than traditional hot isostatic pressing processes.