Silicon Carbide (SiC) is a ceramic material composed of silicon and carbon. Naturally occurring as moissanite in meteorites, mass production of SiC began synthetically since 1893 as an abrasive.
Material with excellent corrosion resistance and low thermal expansion rates, silicon carbide is an increasingly popular refractory material for use in furnaces and can also be used for high temperature components like nozzles.
Hardness
Silicon Carbide Ceramics are highly hard wearing materials, making them suitable for environments such as 3D printing, ballistics and chemical production. Their resistance to wear allows for effortless abrasion and friction wear while their structural integrity protects against mechanical strain. Furthermore, these toxicologically safe ceramics can even be found in food manufacturing and pipe systems for food transportation systems.
SiC’s high hardness can be attributed to its unique crystal structure, consisting of carbon and silicon atoms bonded tightly by strong bonds within its crystal lattice. Furthermore, this material is resistant to acids, alkalis and molten salts while being insoluble at temperatures up to 1600degC without losing strength.
Other elements which impact silicon carbide hardness include its purity; with lower impurity levels correlated to higher hardness. Sintering degree also plays a vital role in this respect; higher heating levels during manufacturing result in greater hardness.
Silicone carbide hardness can be further increased through surface treatment methods such as coating and plating to reduce wear, improve lubrication and increase corrosion resistance. Thermal spray, cold spray and physical vapor deposition (PVD) techniques all produce thick and durable coating layers on silicon carbide surfaces; various materials can be employed depending on application needs for this process.
Corrosion Resistance
SiC is highly resistant to acids and alkalis at various concentrations, as well as corrosion from metal molten deposits such as nickel slag, uranium melts and zirconium melts.
PVC sheet can be easily formed into large structural shapes and offers exceptional load-bearing capacity at higher temperatures, thanks to its high Young’s modulus (more than 400 GPa). Tight dimensional tolerances and excellent machinability enable tight dimensional tolerances as well as excellent machining capability – making PVC an invaluable component for modern lapidary due to its hardness, durability and relatively low cost.
Silicon carbide and silicon nitride both exhibit exceptional resistance to erosion, abrasion and corrosion due to an oxide barrier on their surfaces that prevents direct contact between attacking species and substrate material. Furthermore, parabolic corrosion reaction kinetics could be attributable to this protective layer as well.
Silicon carbide forms in its bulk form as a close-packed structure composed of covalently bonded atoms, typically in hexagonal form called a-SiC, with its crystal structure similar to Wurtzite. Other varieties such as cubic form, called b-SiC with zincblende crystal structure or three additional varieties whose stacking arrangements resemble those of cube are also possible.
Thermal Conductivity
Silicon carbide’s excellent thermal conductivity enables it to withstand temperatures of up to 1,400degC without weakening or cracking, making it suitable for use in thermally demanding environments like chemical plants and kilns. Furthermore, SiC is adept at resisting corrosion, abrasion and erosion challenges in mills, expanders and nozzles – perfect for many thermally demanding situations!
Silicon carbide’s rigidity and low thermal expansion also makes it a desirable material for mirrors in astronomical telescopes, making some of the largest telescopes worldwide use silicon carbide mirrors as mirrors.
Silicon carbide’s hardness also lends it itself to effective machining. In its green or biscuit (fully unsintered) forms, silicon carbide can be machined using conventional ceramic forming processes and diamond tools; when sintered however, its size shrinks by around 20% making tight tolerances impossible to attain.
IPS manufactures silicon carbide ceramic components using various forming techniques, such as reaction bonding and direct sintered SiC. Sintering methods have an impactful influence on the microstructure of final products; for instance, reaction bonding involves infiltrating compacts formed from mixtures of SiC and carbon with liquid silicon which reacts with it and forms more SiC particles, adhering them together with stronger bonds than initial particles formed in reaction bonding. Reaction sintering provides the most cost-effective means of producing large size complex shaped products while simultaneously creating raw granular silicon carbide material suitable for further processing or preparation into final form.
Thermal Shock Resistance
Ceramic materials must withstand thermal shock in many applications. Thermal shock resistance refers to a material’s ability to maintain strength, hardness and chemical stability when subjected to sudden temperature shifts. Ceramics that are thermally stable can absorb high levels of mechanical stress easily, making them suitable for aerospace applications like flight control components or advanced propulsion systems.
Silicon carbide offers outstanding thermal shock resistance due to its extremely low coefficient of expansion and high tensile strength, making it an excellent material choice for thermal shock applications such as spray nozzles and cyclone components. Due to its resistance against physical wear, silicon carbide makes an ideal material choice when applied against physical wear in applications like spray nozzles and cyclone components.
This material is also ideal for harsh environments, including chemical production and energy technology, where it’s often employed as high-temperature refractory products. Saint-Gobain produces Hexoloy RS-SiC technical ceramics which withstand both extreme temperatures and corrosive materials, including flue gas desulphurization plants.
Since 1891 when discovered by Pennsylvania chemist Edward Goodrich Acheson, silicon carbide has proven itself an exceptional ceramic material with impressive physical, mechanical, and thermal properties. Due to its combination of strength, chemical inertness, and thermal stability, silicon carbide has become an indispensable industrial material in today’s demanding technologies and industries; making its presence indispensable across a range of sectors including wear-resistant components due to its hardness; heat endurance in refractories for its low thermal expansion rate; corrosion protection within ballistic protection applications without impacting vehicle weight or range or operating costs – making silicon carbide an indispensable material in many fields!