Carborundum: A Comprehensive Guide to Its Types, Uses, and Advantages

What is Carborundum?

Carborundum, also known as silicon carbide (SiC), is a crystalline compound of silicon and carbon. Known for its extraordinary hardness and thermal conductivity, it is widely used in industries ranging from aerospace to electronics.

History and Evolution of Carborundum

Discovered in 1891 by Edward G. Acheson, Carborundum was the first man-made abrasive. The Acheson process, which fused silica sand and carbon in an electric furnace, revolutionized industrial manufacturing, introducing a material nearly as hard as diamond.

Chemical Composition and Properties

Carborundum is composed primarily of silicon (Si) and carbon (C) atoms arranged in a hexagonal crystal structure. Key properties include:

• Hardness: 9.5 on the Mohs scale (just below diamond)

• Melting Point: >2700°C

• Thermal Conductivity: High, ideal for heat-intensive applications

• Electrical Conductivity: Variable; can act as a semiconductor

Different Types of Carborundum

Black Carborundum

• Most commonly used variety

• Contains about 98.5% SiC

• Ideal for grinding cast iron, non-ferrous metals, and rubber

Green Carborundum

• Higher purity (up to 99%)

• Used for grinding glass, ceramics, and titanium

Coated vs Bonded Carborundum Abrasives

• Coated: Sandpaper, belts; grit is adhered to a flexible backing

• Bonded: Grinding wheels; grit is bonded with a matrix (vitrified or resin)

Microgrit and Macrogrit Carborundum

• Microgrit: Finer grains (used in polishing and semiconductors)

• Macrogrit: Coarser grains (used in heavy-duty abrasives)

Major Uses of Carborundum

Abrasives and Cutting Tools

• Common in grinding wheels, cutting discs, lapping compounds

• Efficient on tough materials like metal alloys and stone

Refractories and Foundry Work

• Used in furnace linings, crucibles, and kiln shelves due to its thermal stability

Semiconductor Industry

• High-performance SiC wafers are used in diodes, MOSFETs, and power electronics

Automotive and Aerospace Applications

• Carborundum-coated brake pads and clutches resist extreme friction and heat

Decorative and Non-Slip Surfaces

• Added to stair treads, tiles, and walkways for grip and aesthetics

Advantages of Using Carborundum

• High Hardness: Suitable for cutting and grinding hard materials

• Thermal Resistance: Ideal for high-temperature environments

• Chemical Stability: Inert in most chemical settings

• Durability: Long-lasting under mechanical stress

• Eco-Friendliness: Recyclable and energy-efficient in modern production

Carborundum vs Other Abrasives

How Carborundum is Manufactured

The Acheson process is still the primary manufacturing method:

1. Mixing: Silica sand and petroleum coke are combined.

2. Heating: Electric current heats the mix in a graphite crucible.

3. Crystallization: SiC crystals form over 24-48 hours.

4. Crushing and Sizing: Crystals are broken and graded by particle size.

Modern improvements include gas-phase deposition for high-purity electronics-grade SiC.

Environmental and Safety Considerations

While non-toxic in solid form, dust from grinding SiC can cause respiratory irritation. Proper ventilation and protective equipment are recommended. Additionally, SiC manufacturing is being adapted to reduce carbon emissions and energy consumption.

Top Global Manufacturers and Suppliers

• Saint-Gobain (USA/France)

• FerroTec Corporation (Japan)

• CUMI – Carborundum Universal Ltd. (India)

• 3M Abrasives

• Washington Mills

These companies offer everything from raw SiC grit to semiconductor wafers and bonded abrasives.

Frequently Asked Questions

1. Is Carborundum the same as silicon carbide?

Yes. Carborundum is the trademark name for silicon carbide (SiC), especially when used in abrasives.

2. Can Carborundum cut metal?

Absolutely. It is ideal for cutting and grinding metal alloys, especially stainless steel and cast iron.

3. Is Carborundum expensive?

It is moderately priced—cheaper than diamond but more expensive than aluminum oxide.

4. Can it be used in electronics?

Yes. High-purity SiC is used in semiconductors for its superior thermal and electrical properties.

5. Where can I buy Carborundum products?

Check industrial suppliers like Saint-Gobain, CUMI, or online marketplaces such as Alibaba or Amazon for various forms of SiC.

6. Is it eco-friendly?

SiC is recyclable and, with modern processes, can be produced with lower environmental impact.

Conclusion: Why Carborundum Remains Indispensable

From its humble beginnings as a man-made abrasive to its role in high-tech electronics, Carborundum has stood the test of time. Its unmatched hardness, thermal resilience, and versatile applications make it an invaluable material in countless industries. Whether you’re grinding metal or powering semiconductors, Carborundum delivers durability and precision where it matters most.