Silicon Carbide

Silicon carbide (SiC) is an exceptional material with outstanding physical properties. It is resistant to high temperatures, corrosion and wear while possessing low thermal expansion rates.

Moissanite occurs naturally in very limited quantities as a mineral, and has since been mass produced via Edward G. Acheson’s electric batch furnace process which continues to this day.

Characteristics

Silicon carbide offers exceptional chemical and mechanical strength across a wide temperature spectrum, resisting corrosion and abrasion with its high elastic modulus and low coefficient of thermal expansion coefficients. Furthermore, silicon carbide exhibits good resistance to thermal shock, though less so than structural ceramic zirconia.

SiC is generally an electrical insulator; however, with controlled addition of impurities it can become electrically conductive. When doped with aluminum, boron or gallium it becomes P-type semiconductor while nitrogen or phosphorus doping gives rise to N-type semiconductor properties.

Pure industrial SiC is brown to black in color due to iron impurities. As a polytype semiconductor material, its crystal structures vary with respect to how carbon and silicon atoms stack into tetrahedra; this allows it to behave either as an insulator or conductor at constant temperatures; furthermore it remains insoluble in both water and alcohol but resistant to most organic acids, alkalis, and salts.

Applications

Silicon carbide ceramics have applications across numerous fields: from abrasive and cutting tools, structural materials (bulletproof vests and composite armor), automobile parts such as brake disks and lightning arresters to high resistance to corrosion and abrasion environments like petrochemical production plants or flue gas desulphurization systems.

SiC power devices take advantage of its wide bandgap semiconductor properties to conduct at higher voltages, making for more compact power conversion systems with reduced energy loss and shorter conversion times. Furthermore, SiC devices outshone silicon counterparts when it came to switching current and temperature performance compared to their silicon counterparts resulting in significant efficiency gains for end products.

Silicon carbide (SiC) is rapidly revolutionizing power electronics due to its unique combination of physical and electronic properties. MOSFETs and Schottky diodes made of SiC are power semiconductor technologies widely utilized, and form key components in electric vehicles’ traction inverters and on-board chargers as well as DC/DC converters found at charging stations – this translates to improved battery range in electric vehicles and increased efficiency for industrial applications.

Manufacturing

Silicon carbide can be made into an array of materials for various uses. Mechanical engineers rely on it as an advanced ceramic for its strength, hardness, corrosion and wear resistance as well as electrical engineers who use its exceptional electrical properties as semiconductors. Furthermore, silicon carbide plays an integral part of composite armour such as Chobham armour or ceramic plates found in bulletproof vests.

Edward Goodrich Acheson first artificially synthesized SiC in 1891 while trying to produce synthetic diamonds. While creating hard, blue-black crystals that he named carborundum due to being misdiagnosed as corundum like compound, his method has since become the basis of most SiC production today.

Purity of crystals produced in an Acheson furnace varies with their distance from a graphite resistor heat source; those closest to it tend to be clear while those further away tend to become darker with nitrogen or aluminium doping, which reduce conductivity. Large single crystals produced commercially through modified Lely processes or physical vapor transport.

Safety

Silicon carbide dust can be an irritating nuisance that may contribute to nonprogressive pulmonary fibrosis and cause irritation of nose and eyes. Prolonged exposure may even lead to pneumoconiosis – a chronic lung condition with symptoms including abnormalities on chest x-rays and loss of lung function; additionally it increases your risk for tuberculosis.

Due to its superior hardness and stiffness, carbon fiber armour provides ballistic protection at much lower product weight than traditional steel solutions.

Nuclear applications make use of SiC cladding due to its outstanding irradiation performance, surpassing Zry-4 at Tresca stress levels of primary Tresca stress and beyond, with still maintaining an acceptable shutdown margin. Furthermore, it boasts a lower neutron absorption cross section; both SS-310 and FeCrAl claddings exhibit marginally more negative MTC values at BOL than SiC; however this decreases significantly after 5 s of LBLOCA due to Doppler broadening of fertile neutrons.