Silicon Carbide

Silicon carbide (SiC), also known as carborundum, is a versatile ceramic material characterized by its exceptional hardness, high thermal conductivity, and chemical inertness. It finds widespread use in numerous industrial and technological applications. Here are some key parameters for silicon carbide:

  1. Chemical Formula: SiC
  2. Molecular Weight: Approximately 40.1 g/mol
  3. Crystal Structure: SiC exists in over 200 polymorphic forms, with the most common being hexagonal (α-SiC) and cubic (β-SiC) structures.
  4. Density: Theoretical density ranges from 3.18 to 3.21 g/cm³.
  5. Melting Point: Silicon carbide has an incredibly high melting point, around 2700°C in its α-form and slightly lower for β-form.
  6. Hardness: SiC is one of the hardest materials available, with a Mohs hardness rating of 9.5, approaching that of diamond (10).
  7. Thermal Conductivity: It possesses an outstanding thermal conductivity, typically ranging from 100 to 490 W/(m·K), depending on the polytype and purity, making it an excellent heat spreader.
  8. Thermal Expansion Coefficient: The thermal expansion coefficient is low, approximately 2.7 to 4.7 × 10^-6 /°C, contributing to its thermal shock resistance.
  9. Chemical Stability: Silicon carbide is highly resistant to chemical attack, withstanding most acids and alkalis at room temperature, excluding hydrofluoric acid and strong alkalies at high temperatures.
  10. Electrical Properties: Depending on the type, silicon carbide can be semi-conducting or conductive. It is used in high-temperature electronics and power devices due to its wide bandgap.
  11. Mechanical Strength: SiC demonstrates high compressive strength, typically over 400 MPa, and excellent wear resistance.
  12. Synthesis: Silicon carbide is synthesized through several methods, including the Acheson process (an electro-thermal process), chemical vapor deposition (CVD), and sintering of SiC powders.

  13. Applications: It is used in abrasives, refractories, ceramic plates and armor, semiconductor devices, high-temperature heating elements, and as a substrate material in LED and high-power electronic devices.

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