| Silicon Carbide, SiC Silicon Carbide is the only chemical compound of carbon and silicon. It was originally produced by a high temperature electro-chemical reaction of sand and carbon. Silicon carbide is an excellent abrasive and has been produced and made into grinding wheels and other abrasive products for over one hundred years. Today the material has been developed into a high quality technical grade ceramic with very good mechanical properties. It is used in abrasives, refractories, ceramics, and numerous high-performance applications. The material can also be made an electrical conductor and has applications in resistance heating, flame igniters and electronic components. Structural and wear applications are constantly developing. | .Key Properties |  | Low density | | High strength | | Low thermal expansion | | High thermal conductivity | | High hardness | | High elastic modulus | | Excellent thermal shock resistance | | Superior chemical inertness | .
Typical Uses | | Fixed and moving turbine components | | Suction box covers | | Seals, bearings | | Ball valve parts | | Hot gas flow liners | | Heat exchangers | | Semiconductor process equipment | General Information
Silicon carbide is composed of tetrahedra of carbon and silicon atoms with strong bonds in the crystal lattice. This produces a very hard and strong material. Silicon carbide is not attacked by any acids or alkalis or molten salts up to 800°C. In air, SiC forms a protective silicon oxide coating at 1200°C and is able to be used up to 1600°C. The high thermal conductivity coupled with low thermal expansion and high strength give this material exceptional thermal shock resistant qualities. Silicon carbide ceramics with little or no grain boundary impurities maintain their strength to very high temperatures, approaching 1600°C with no strength loss. Chemical purity, resistance to chemical attack at temperature, and strength retention at high temperatures has made this material very popular as wafer tray supports and paddles in semiconductor furnaces. The electrical conduction of the material has lead to its use in resistance heating elements for electric furnaces, and as a key component in thermistors (temperature variable resistors) and in varistors (voltage variable resistors). Back to top Engineering Properties* | Silicon Carbide | | Mechanical | SI/Metric (Imperial) | SI/Metric | (Imperial) | | Density | gm/cc (lb/ft3) | 3.1 | (193.5) | | Porosity | % (%) | 0 | (0) | | Color | — | black | — | | Flexural Strength | MPa (lb/in2x103) | 550 | (80) | | Elastic Modulus | GPa (lb/in2x106) | 410 | (59.5) | | Shear Modulus | GPa (lb/in2x106) | — | — | | Bulk Modulus | GPa (lb/in2x106) | — | — | | Poisson’s Ratio | — | 0.14 | (0.14) | | Compressive Strength | MPa (lb/in2x103) | 3900 | (566) | | Hardness | Kg/mm2 | 2800 | — | | Fracture Toughness KIC | MPa•m1/2 | 4.6 | — | Maximum Use Temperature
(no load) | °C (°F) | 1650 | (3000) | | Thermal | | | | | Thermal Conductivity | W/m•°K (BTU•in/ft2•hr•°F) | 120 | (830) | | Coefficient of Thermal Expansion | 10–6/°C (10–6/°F) | 4.0 | (2.2) | | Specific Heat | J/Kg•°K (Btu/lb•°F) | 750 | (0.18) | | Electrical | | | | | Dielectric Strength | ac-kv/mm (volts/mil) | — | semiconductor | | Dielectric Constant | — | — | — | | Dissipation Factor | — | — | — | | Loss Tangent | — | — | — | | Volume Resistivity | ohm•cm | 102–106 | dopant dependent | *All properties are room temperature values except as noted.
The data presented is typical of commercially available material and is offered for comparative purposes only. The information is not to be interpreted as absolute material properties nor does it constitute a representation or warranty for which we assume legal liability. User shall determine suitability of the material for the intended use and assumes all risk and liability whatsoever in connection therewith. Back to top Standard Products | Custom Products and Services | Case Studies | Materials
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