Silicon Carbide Thermal Conductivity

Silicon carbide, or carborundum (), is a hard ceramic first mass-produced in 1893 for use as an abrasive. While natural instances exist (moissanite gems and small quantities as an igneous rock called corundum), most modern day usage occurs synthetically.

SiC is known to exhibit high fatigue resistance, high thermal conductivity and a low coefficient of expansion; making it suitable for fabrication to withstand high temperatures while remaining strong under corrosive environments.

Thermophysical Properties

Silicon carbide is one of the few materials with high thermal conductivity at room temperature. Due to its hard, rigid, and temperature stable nature, silicon carbide makes an excellent material choice for use in telescope mirrors used by astronomers.

Density Functional Theory was utilized for systematic theoretical investigations of the structural parameters and finite-temperature thermo-physical properties of cubic silicon carbide (3C-SiC). Our results regarding elastic constants and Knoop micro hardness showed satisfactory agreement with experimental data as well as calculated findings published elsewhere.

By employing optimized structure models, we also obtained atomic-level estimates of defect formation energies for ZrC, TiC and SiC using optimized structure models. The results revealed that Debye temperature decreases with increasing numbers of defect atoms while CZr antisite and VC defects exhibit lower formation energies than their counterpart VSi and Sit defects; their formation energy reduction may impact resistance against uniaxial and shear deformation of 3C-SiC structures.

Electrical Properties

Silicon carbide is one of the hardest and most thermally conductive materials found in nature, resisting both acids and alkalis attacks while being heat resistant up to 1600 degC without strength loss. Furthermore, silicon carbide makes an excellent electrical conductor.

Silicon carbide’s wide bandgap makes it suitable for use in semiconductor devices like diodes, transistors and thyristors, while its ability to withstand large voltages and currents make it useful in high-power power devices as well.

Porous SiC can be altered by adding graphene nanoplatelets (GNPs), creating a material with enhanced thermal properties. This material can be manufactured via liquid-phase spark plasma sintering of either stoichiometric or off-stoichiometric SiC powder; various combinations of sintering aids (Y2O3 and La2O3) were tested to evaluate their effects on phase composition, microstructure and thermal conductivity of porous materials with up to 20 vol% GNPs content; non-monotonic temperature dependence was observed with composites containing up to 20% GNP content.

Mechanical Properties

SiC’s unique composition of silicon and carbon atoms in its crystal lattice gives it remarkable mechanical properties that make it one of the toughest and hardest ceramic materials. Highly resistant to corrosion from acids, lyes, molten salts as well as abrasion; rigidity and strength make SiC an attractive material choice for wear-resistant components such as grinding wheels or drill bits in mills, expanders or extruders as well.

As well as being lightweight, ceramic material exhibits excellent thermal shock resistance – it can withstand temperatures up to 1600degC without losing its mechanical properties or thermal expansion, with low thermal expansion rates and an exceptionally high Young’s modulus providing dimensional stability.

Porosity in porous SiC ceramics varies depending on their forming method (reaction bonding or sintered). Studies have demonstrated that both electrical conductivity and flexural strength increase with increasing B4C content due to its ability to adsorb oxygen from Si-C matrix materials and thus decrease phonon scattering length.

Applications

Silicon carbide is used as both an abrasive and cutting tool in manufacturing. Due to its hard and heat-resistant surface, silicon carbide can also be found as an electronic semiconductor in diodes and transistors as its voltage tolerance can surpass that of silicon.

Silicon carbide’s hardness, resistance to corrosion and high thermal conductivity make it an excellent material for protective equipment such as helmets and armor plates. Furthermore, its chemical inertness means it does not react with water making it ideal for use in high humidity settings such as spacecraft and marine environments.

Recrystallized silicon carbide (RSiC) boasts an unmatched blend of mechanical, thermal and electrical properties than any other SiC variants. Its dense microstructure gives RSiC low coefficient of expansion while also maintaining strength and rigidity at high temperatures; plus it displays relatively higher elastic modulus values than structural zirconia ceramic and has low thermal expansion coefficient values compared with structural zirconia ceramic.

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