Silicon carbide is one of the hardest and most resilient ceramic materials, offering outstanding corrosion resistance and high temperature strength properties. This material makes an especially great choice in environments requiring corrosion resistance or high temperature strength.
Carborundum, composed of silicon and carbon compounds, naturally occurs as the rare mineral moissanite but has been mass produced since 1893 for use as an abrasive.
Hardness
Silicon Carbide boasts an extremely high hardness that makes it suitable for mechanical and wear applications, including those involving mechanical contact with water or moisture. As an excellent machining material, silicon carbide has many applications within industry including machine parts for machine processing equipment such as semiconductor processing plants as well as general industrial use due to its chemical stability, corrosion resistance and low coefficient of friction – it even maintains strength at temperatures up to 1400 degC! Plus it’s electrically semi-conductive!
Silicon carbide’s crystal structure resembles that of diamond, featuring carbon and silicon atoms arranged into tetrahedra. This contributes to SiC’s exceptional properties such as high temperature strength, excellent oxidation resistance and thermal shock resistance, hardness, and hardness (only other material is harder: boron nitride with Brinell hardness of 2700 degC).
Fabricating siliconized silicon carbide requires several methods of production. Commercially available sintered silicon carbide (SSiC), like Saint Gobain’s Hexoloy, is typically created through reaction bonding porous SiC powder with powdered carbon and plasticizer for reaction bonding before sintering; alternative fabrication techniques include dry-pressing and extrusion.
Elkem’s specialized process for producing siliconized silicon carbide, known as EPS, yields ceramic with superior bending strength compared to carbon graphite – particularly when the particle size decreases due to Elkem’s reduction of original SiC powder particles. This gives Elkem an edge in terms of ceramic production that rivals carbon graphite products.
Thermal Conductivity
Silicon carbide ceramic has an exceptionally high thermal conductivity compared to other ceramics. Furthermore, its semiconducting nature and good resistance to corrosion make it suitable for many chemical environments. Furthermore, this hard material has very low thermal expansion rates and can withstand temperatures up to 1400degC without suffering significant strength degradation.
Due to its strong bonds within its crystal lattice, this material exhibits exceptional chemical resistance. It does not react negatively with acids, alkalis or molten salts, while at the same time providing superior erosion resistance and wear characteristics.
Saint Gobain SiSiC and NSiC products provide maximum precision and accuracy in industrial metrology equipment that must operate at high temperatures and precision positioning of axes, such as industrial metrology. Their superior stability over traditional alumina or aluminum ceramics also make them the go-to choice.
Silicon carbide also boasts excellent resistance to abrasion and corrosion, operating at very high temperatures with little loss in properties such as hardness or stiffness. Together these attributes make silicon carbide an exceptionally versatile structural ceramic.
Silicon carbide is lightweight and has excellent dimensional stability, making it suitable for fabricating into different shapes and sizes to meet customer requirements. Due to this versatility, silicon carbide has become one of the most sought-after structural ceramic materials used across a variety of industries such as but not limited to:
Thermal Expansion Coefficient
Silicon carbide (commonly referred to as carborundum) was initially created through electro-chemical reaction between sand and carbon, yielding a hard chemical compound known as silicon carbide or carborundum that can be densified into blocks, slabs or even gems. With its wide bandgap semiconductor properties and low thermal expansion coefficient it makes silicon carbide an excellent material choice for use at higher temperatures or elevated pressures.
Studies of 3C-SiC obtained through X-ray powder diffraction reveal its lattice parameter is approximately 4.596 A with nearly flat phonon dispersion curves. Computational thermal expansion values obtained via Gruneisen formalism and CASTEP codes approach approximately 2.4x 10-6/degC for room temperatures.
Thermal expansion in SiC depends primarily on its crystal structure and the way in which atoms are arranged in it, with slight anisotropies for measurements parallel and perpendicular to its c-axis.
Silicosis, caused by breathing in dust containing silica particles or fibers, is a serious and chronic lung condition similar to coal miner’s lung disease or asbestosis. Workers manufacturing or using carborundum abrasives are more prone to this illness; its symptoms resemble those seen among smokers and may include progressive, fibrotic pulmonary disease that may prove fatal; it has also been associated with increased rates of lung cancer and heart attack.
Electrical Conductivity
Silicon carbide (SiC) is a wide-band semiconductor material, with a bandgap width ranging between 2.2 to 3.3 electron volts (eV). Materials with narrower or wider band gaps behave as either conductors or insulators respectively; due to SiC’s wider band gap it allows it to operate at higher temperatures than other semiconductor devices.
Material with excellent electrical properties such as aluminum makes it an attractive choice for electronics applications, including light-emitting diodes (LEDs) and transistors. Furthermore, its excellent tribological properties make it suitable for components such as sliding rings, pump impellers and ship propellers.
Silicon Carbide is an ideal material for insulating high-voltage circuits within inverters to increase driving range while decreasing energy efficiency. Thanks to its strength, oxidation resistance, thermal properties and durability it improves performance, reduces system size/weight/reliability significantly and ensures reliable operation.
To optimize the performance of siliconized silicon carbide composites, various surface treatments were investigated. These included PSZ and silicon carbonitride coatings applied directly onto SiC particles before being introduced into a matrix; then tested for thermal and electrical conductivity.
Converted graphite materials that feature sufficient porosity for silicon infiltration can serve as the starting material for siliconization processes, with 5 vol % to 29 vol % porosity serving as ideal starting material.
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