Silicon Carbide (SiC) is a nonoxide ceramic material commonly found in products designed for harsh conditions. Applications for SiC include refractories and abrasives used for their hardness and wear resistant parts used in car brakes as well as bulletproof vests.
Sintered SiC, more commonly referred to as SSiC, is produced by sintering SiC powder. Saint-Gobain offers several formulations of SSiC such as reaction bonded, dry-press and extruded varieties.
Hardness
Silicon carbide (SiC) is one of the hardest materials known to man and often compared to diamond. Used in abrasive applications and bulletproof armor manufacturing processes, SiC features low thermal expansion rates as well as exceptional acid-resistance properties while boasting outstanding mechanical properties.
SiC’s hardness can be attributed to its crystal structure and bonding properties, with regular arrangements of atoms that is neither brittle nor fragile; this contributes to its high strength. Another factor contributing to SiC’s hardness is its wide bandgap (the energy needed for electrons to jump from its valence band to conduction band of an atom), where conductors typically possess narrower gaps while insulators feature wider ones.
SiC is valued for its hardness, which makes it suitable for ballistic applications such as bulletproof armor. Ceramic plates used as armor must withstand even extremely hard projectiles without shattering under impact from moving projectiles of different speeds and velocities. Researchers conducted tests using projectiles traveling at various velocities with the goal of testing ceramic durability; results revealed that composite ceramics (alumina-silicon carbide combination ceramics in particular) outshone pure alumina ceramics by providing resistance up to 850m/s– a remarkable accomplishment given their combination of hardness and light weight properties.
Thermal Conductivity
Silicon carbide is an exceptional thermal conductor with low coefficient of expansion and high strength, boasting superior chemical inertia, thermal conductivity, thermal shock resistance and chemical inertia properties, making it a prime candidate for use in high temperature applications.
Aluminum alloy is resistant to corrosion in most acids (hydrochloric, sulfuric, phosphoric and hydrofluoric acids), alkalis and molten salts, and remains remarkably inert when exposed to most oxidizing environments such as nitric acid, oxygen or air. Furthermore, its mechanical strength remains undiminished even at temperatures reaching 1600 degC; making it the ideal material choice for use in electric vehicle inverters which must operate at high voltages and temperatures.
Silicon carbide is most often seen in its alpha-SiC polymorph form with its hexagonal crystal structure resembling that of Wurtzite; less frequently found is beta-SiC’s zinc blende structure similar to diamond.
Workers exposed to dust created during production may develop diffuse interstitial pulmonary fibrosis. Exposure to fine dust made up from production can exacerbate this disease, increasing risks such as lung cancer and respiratory distress such as coughing, wheezing, bronchitis and shortness of breath – not immediately fatal but potentially life-threatening over time. Electric vehicle inverter manufacturers can avoid these risks by opting for ceramic materials like boron nitride and silicon carbide to create durable high-performance products with minimal wear and tear abrasion resistance.
Resistance to Corrosion
Silicon carbide is one of the hardest materials on Earth; only diamond, cubic boron nitride and tungsten carbide surpass its hardness. Furthermore, silicon carbide’s thermal stability allows it to withstand high temperatures without incurring damage.
Silicon carbide excels at corrosion resistance. It stands up well against acids (hydrochloric, sulfuric and nitric) and bases (alkalis and potash), in addition to solvents and oxidizing agents – an impressive ability that makes silicon carbide an excellent material choice for many industrial process applications.
Silicon carbide’s chemical stability in acidic or alkaline environments has also attracted considerable consideration, making it an indispensable material choice for use in chemical engineering applications and energy conversion systems that often operate under harsh conditions that limit other materials’ practical application.
SiC is found naturally in very small quantities; most notably in Arizona’s Canyon Diablo meteorite where it was named moissanite after being discovered by Edward Goodrich Acheson in 1891. But for industrial and commercial uses, SiC must be synthesized. This involves heating together silicon sand with carbon in an electrical resistance-type furnace heated by electric current passing through a carbon conductor; heating also activates an electrochemical reaction that produces SiC.
Wear Resistance
Silicon carbide boasts excellent wear resistance, making it an excellent material to combine with graphite to produce composite materials. Furthermore, silicon carbide has high chemical resistance as well as being capable of withstanding high temperatures and hostile fluid environments.
Ceramic is an ideal material to use when it is exposed to friction and heat, such as brakes or clutches or ceramic plates used in bulletproof vests. Furthermore, its resistance to high voltage currents makes it a suitable material for electrical insulation applications.
At present, titanium is one of the hardest-known materials, rivalling such hard substances as diamond and boron carbide in terms of hardness. This hardness helps it resist wear-and-tear wear, corrosion and oxidation; additionally it’s highly rigid with low thermal expansion coefficient allowing it to remain stable under changing temperature conditions.
Palace and Arikan determined that SiC was the optimal material to use in body armor applications, considering its volumetric, weightatic and cost criteria. As potential alternatives they investigated alumina (Al2O3), silicon nitride (Si3N4) and boron carbide (B4C). They evaluated each alternative’s composite structure and optimal layer thickness before selecting SiC as their material of choice for body armor applications.
Junty employs only products composed of RB SiC and SSiC without free silicon in our products, as these materials offer maximum chemical resistance in harsh environments while still performing at high temperatures. As such, our silicon carbide products are well suited to a range of applications including spray nozzles and shot blast nozzles, kiln furniture (posts, pusher slabs and girders), lightweight kiln linings and lightweight kiln furniture (posts/girders/girders/girders).