Black silicon carbide (SiC) is a synthetic abrasive material produced by reacting silica sand and petroleum coke in an electric resistance furnace at high temperatures (around 2200°C). It is one of the hardest synthetic abrasives, with a Mohs hardness of 9–9.5, second only to diamond and boron carbide.
Key Properties of Black Silicon Carbide:
Hardness: Extremely hard and sharp, making it ideal for abrasive applications.
Thermal Stability: Maintains strength at high temperatures (up to 1600°C).
Chemical Resistance: Resistant to acids and alkalis.
Brittleness: More brittle than green silicon carbide, making it better suited for certain grinding and blasting applications.
Conductivity: Semi-conductive properties, useful in some electronic applications.
Applications of Black Silicon Carbide:
Abrasive Tools: Used in grinding wheels, sandpaper, and cutting discs for metals, ceramics, and stone.
Lapping & Polishing: Effective for finishing hard materials like tungsten carbide and glass.
Refractory Materials: Added to high-temperature ceramics and furnace linings for improved durability.
Wire Sawing: Used in cutting hard stones like granite and marble.
Surface Blasting: Employed in sandblasting for cleaning and etching metal surfaces.
Anti-Slip Coatings: Mixed into paints or coatings for slip-resistant surfaces.
Electronics: Used in some semiconductor and LED applications due to its thermal conductivity.
Black silicon carbide (SiC) is a highly durable and refractory material often used in high-temperature applications, including crucibles. Here’s why it’s a good choice and some considerations:
Advantages of Black Silicon Carbide for Crucibles:
High Thermal Conductivity – Efficient heat transfer ensures uniform heating.
Excellent Thermal Shock Resistance – Resists cracking under rapid temperature changes.
High Melting Point (~2,700°C) – Suitable for extreme heat applications.
Chemical Inertness – Resists corrosion from molten metals, acids, and slags.
Mechanical Strength – Hard and abrasion-resistant, maintaining structural integrity.
Common Uses:
Melting non-ferrous metals (aluminum, copper, zinc).
High-temperature furnace components.
Foundry applications where durability is critical.
Black SiC crucibles are ideal for high-performance applications where extreme temperatures, thermal cycling, and chemical resistance are critical.