Silicon carbide and silicon carbide ceramics are black, high-strength materials with higher hardness and better thermal shock resistance than alumina. They have superior properties for power devices and are predicted to revolutionize the power electronics industry. These hard ceramics consist of grains of silicon carbide which can be bonded together by sintering.

Silicon carbide ceramics are manufactured using the Acheson process, in which batches of sand (SiO2 or silicon dioxide) and carbon are heated and reacted in an electric furnace. The sponge-like grains are then crushed and processed into abrasive and powder forms.

By sintering fine SiC particles, different types of silicon carbide ceramics can be made. Another production technique involves depositing silicon carbide onto a substrate through a sublimation or chemical vapor deposition (CVD) process.

Moissanite and Hexoloy

To account for special features of silicon carbide and silicon carbide ceramics, a natural form exists as Moissanite, and a man-made single crystal version is sold as Moissanite for gem applications in jewelry. A well-known high-performance variety of silicon carbide ceramic, Hexoloy®, is manufactured by Saint-Gobain. Hexoloy® offers a variety of silicon carbide ceramics with different properties and applications.

Applications

Silicon carbide powders are used to manufacture hard ceramics, refractories, abrasives, and composite reinforcements. Single-crystal products are as used as compounds in semiconductor substrates for high-temperature applications.

Silicon carbide ceramics are also used in:

• Ceramic armor protection systems
• High temperature bearings
• Electric furnace heating elements
• Faucet washers
• Wear resistant nozzles
• Wear parts
• Valve parts
• Mechanical seal faces
• Thermocouple protection tubes
• Kiln system components (batts, beams, posts, rollers and heat exchanger tubing)

Because of their high endurance, these ceramics are also used in products ranging from car brakes to ceramic plates in bulletproof vests.

Silicon carbide is used in:

• Cutting tools
• Structural materials
• Automobile parts
• Electric systems
• Electronic circuit elements
• Mirror material in astronomical telescopes
• Heating elements
• Nuclear fuel elements
• Jewelry
• Catalyst support
• Carborundum printmaking

Silicon carbide ceramics are also used in thin filament pyrometry and steel production.

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CoorsTek