An Overview of Silicon Carbide: Part II | IRD Glass

As discussed in part I, silicon carbide (SiC or carborundum) is a very versatile material used in many applications, from the production of bulletproof vests to the aerospace industry. SiC was first used in the 1800s as an abrasive material, and today precision machining of SiC is a necessity in many industries. Therefore, machined silicon carbide is an optimal choice in many cases. 

However, there are advantages and disadvantages to using carborundum, as with all materials. Read on to learn more about silicon carbide, its applications, and the pros and cons. 

More About Silicon Carbide 

The hardness of carborundum is second only to that of a diamond, and it has earned the nickname of a “super hard ceramic,” along with boron carbide. Its properties of low thermal expansion, chemical resistance, and thermal conductivity also add to its usefulness. Diamond-grinding methods are used to process SiC once it is fired. For use as a machined ceramic, SiC grains are bonded and sintered at extremely high temperatures, forming solid pieces. 

Ideally, SiC is best used in applications where physical wear is an important factor, such as spray nozzles, cyclone components (a device that uses fluid pressure to produce rotational motion), and mechanical seals; however, it has many applications beyond that. 

What Are Silicon Carbide Applications?

The high surface hardness of SiC makes it ideal for applications where erosive and corrosive wear resistance is a necessity. Some industries SiC is used in include:

• Space applications
• Manufacturing of electric vehicles
• Solar energy fields
• Semiconductor manufacturing  

For example, in the space industry, SiC is used to make solar array blocking diodes. These are directly exposed in space and require the highest level of precision. In electric vehicles, carborundum is used to manufacture high-voltage power converters, which must be perfect in weight, size, and efficiency. Some other general applications of SiC include:

• Plungers
• Mechanical seals
• Wear parts (thread guides)
• Kiln furniture crucibles
• Blast nozzles
• Burners
• Valve seals
• Heat exchangers
• Seal rings (water ring pumps)
• Sliding bearings 
• Power electronic components 
• Sandblasting injectors
• Extrusion dies

While silicon carbide is useful in many applications, it does have its pros and cons. 

What Are the Advantages and Disadvantages of Using SiC?

Here is a recap as to why  carborundum is so beneficial:

• High thermal consistency
• High hardness
• Non-linear electrical resistance
• Electrical conductivity
• Resistance to high temperatures

However, there are some drawbacks to using silicon carbide. Some disadvantages include:

• Different types of mineral defects are produced in SiC substrates
• SiC is not a natural mineral, so excessive furnace techniques are needed
• There can be high manufacturing costs due to the difficulty and cost of making large wafers of SiC
• High manufacturing costs from long process cycle times
• High manufacturing costs from excessive tool wear

Here, we can machine and polish SiC. To learn more about silicon carbide, polished ceramics, and our specific applications, please contact IRD Glass here for contact information and directions.