炭化ケイ素の定義

Silicon carbide (SiC) is an inorganic ceramic material widely used in mechanically and thermally demanding applications, second only to boron carbide and diamond in terms of hardness.

Carborundum was first discovered by American inventor Edward G. Acheson while trying to produce artificial diamonds in 1891 and has become an indispensable component in cutting tools and refractory linings ever since.

硬度

Silicon carbide has impressive physical properties, yet is frequently misunderstood and misinterpreted. Hardness is often confused with strength; in reality it refers to materials’ resistance to deformation rather than rigidity or stiffness.

Hardness in materials is determined by its microdurability or small-scale shear modulus in all directions, not its stiffness or Young’s Modulus which depends on various factors including geometry and chemical composition; for instance silicon carbide is much harder than diamond but less stiff than osmium or tungsten, for instance.

Harder materials tend to be more resistant to damage, yet less flexible or elastic than their softer counterparts – hence why toughness and hardness are sometimes used interchangeably.

Silicon carbide boasts the highest hardness of all crystalline compounds, although not quite as hard as diamond. Produced industrially for use as an abrasive and in other metallurgical and refractory applications as well as ceramic production, silicon carbide can also be found as synthetic moissanite jewelry alternatives to natural gemstones.

Silicon carbide-containing composites experience an increase in hardness proportional to their SiC weight percentage, due to being embedded within the matrix and being more resistant to damage and shear forces.

熱伝導率

Silicon carbide possesses high thermal conductivity, meaning that it easily transfers heat. This occurs through molecular vibration and contact between molecules within the material; temperature gradients across its thickness play an essential part in this transference, as does density and crystal structure of its constituent parts.

Thermal conductivity is an essential characteristic for producing advanced ceramics such as those used in automotive brakes and clutches, enabling these materials to operate at higher temperatures without losing their mechanical properties. Ceramic is also widely used as bulletproof vest material as its strength can withstand extremely high levels of force without breaking.

SiC’s high conductivity allows semiconductors made with SiC to operate at much higher frequencies and temperatures than silicon-based transistors and diodes, reducing power losses while increasing reliability.

Silicon carbide’s chemical composition also makes it a highly stable material that resists corrosion, making it one of the most durable industrial and metallurgical ceramics available today. It boasts excellent resistance against chemicals such as hydrochloric, sulphuric and hydrofluoric acids as well as concentrated bases like sodium hydroxide. Furthermore, silicon carbide can even be melted at high temperatures to form strong bonds with glass or other fragile materials like ceramic.

電気伝導率

SiC’s electrical conductivity makes it an invaluable material in power applications, particularly those involving large amounts of current. Thanks to its impressive electrical properties, SiC has emerged as a viable alternative to silicon semiconductors for demanding uses like electric car power electronics and instrumentation on Mars or Venus-bound probes (Mantooth, Zetterling & Rusu).

SiC’s high electrical conductivity can be attributed to its wide bandgap. The gap between valence and conduction bands determines whether a material is either conductor or insulator; with an expansive gap, electrons can move freely from valence band to conduction band while crossing this gap requires prohibitively large amounts of energy for an insulator.

Chemical Vapor Infiltration (CVI) or Polymer Impregnation-Pyrolysis (PIP) of n-type SiC into its matrix increases electrical conductivity by two to three orders of magnitude at elevated temperatures, due to formation of crystals with lower band gaps than pristine silicon carbide. This increase can be attributed to formation of new crystals of SiC with greater electrical conductivity.

Si-SiC material possesses an electrical conductivity between 105 to 107 Ohm*cm due to its low thermal expansion rate and electrical conductivity of 105-107 Ohm*cm per cm squared, making it suitable for applications requiring high currents, temperatures, erosion resistance and corrosion protection. With such properties combined, Si-SiC stands out as an ideal candidate.

Chemical Composition

Silicon carbide is composed of carbon and silicon atoms arranged into four-sided structures bound by strong bonds that make up its crystal structure. These strong bonds give silicon carbide its extremely hard and tough surface that’s also chemical-resistance; its durability also protects it against acid attack as well as thermal shock at up to 1600degC. Furthermore, its excellent resistance to impact damage makes it suitable for applications where physical wear plays a factor such as spray nozzles, shot blast nozzles or cyclone components.

Ceramic nanoparticles are one of the lightest, strongest, and hardest advanced ceramic materials available. It boasts excellent electrical properties with excellent thermal conductivity and low coefficient of thermal expansion; additionally it resists high temperatures as a semiconductor material.

Silicon carbide boasts a wide band gap semiconductor, making it suitable for power electronics. Its voltage resistance is 10 times higher than regular silicon and excels over gallium nitride in systems operating at high speeds or temperatures.

Synthetic diamond production primarily for use as an abrasive is undertaken synthetically; however, other applications of synthetic diamond may include lapidary applications. Due to its long durability and resistance against abrasion, synthetic diamond is frequently utilized by modern lapidaries as an ingredient due to its durability and resistance against wear-and-tear damage. Furthermore, synthetic diamond can also be found used as an abrasive in grinding tools, automobile parts and refractory materials – as well as being hard, durable and helpful when combined with materials such as steel and tungsten carbide in machining applications combined with other hard and durable materials like steel and tungsten carbide for enhanced results.