What is silicon carbide?

Silicon carbide: Basic chemistry and processing techniques

A mixture of a carbon material and a silica or quartz sand is made to react chemically, resulting in the formation of SiC, which develops as a solid cylindrical ingot around the core, with radial layers ranging from graphite in the inside to ­α-SiC (the highest-grade material with coarse crystalline structure), β-SiC, metallurgical grade and finally unreacted material on the outside, which is remelted. SiC can be produced in either black or green, depending on the raw materials used.

Once it is cooled, the SiC ingots are sorted accurately by skilled workers and further processed for different applications. The solid SiC material is then carefully crushed, classified, and milled again if necessary. Another option is to further chemically treat the SiC to obtain specific properties for its applications.

Features of silicon carbide

Silicon carbide provides benefits for high-temperature, high-voltage and high-power applications. These include:

• Great mechanical strength, including high levels of hardness
• Great high-temperature resistance, combined to low thermal expansion and high thermal consistency
• Chemical inertness at all temperatures
• Variable electrical conductivity, including semiconductor properties and non-linear electrical resistance.

Applications of silicon carbide

Thanks to its versatile properties, silicon carbide is a widely used ceramic material in many high-temperature and wear-resistant applications, such as:

• Refractory applications in the production of iron, steel, ceramics, nonferrous metals, energy, chemicals, etc.
• A high-temperature gas sensor in devices in chemical production and in turbine or engine testing to detect flammable and combustible gases in harsh, high-temperature, and corrosive environments
• Ceramic welding powders
• Semiconductors in electronics for circuit elements thanks to its high-voltage resistance

Elkem's silicon carbide products

Elkem's silicon carbide products are available in different grades and qualities, with purities from 87% up to 99%. Based on the raw material used, SiC can be produced either in green or black.

• The silicon carbide SICAREPS™ line is available in different qualities (from 92 to 98% purity) and particle sizes. and is mainly used in refractory applications.
• SICAREPS™ 'F' MICRO and MACRO products are semi-friable black SiC abrasives, used in all abrasive applications, including ceramics, blasting, glass polishing, etc. They are also used in the manufacture of precision grinding wheels.

Please contact our specialists or salespeople in your area for further information and advice.

Elkem silicon carbide: A best-in-class choice

Elkem silicon carbide products are prepared to customer specifications in our state-of-the-art facility in Liège, Belgium, operating under the name of Elkem Processing Services (EPS). EPS is focused on sourcing and processing SiC, and is currently developing its activities to supply specialized products to its existing customers and developing its offer beyond, internationally and to other industries.

The highly competent staff of EPS provides full customer services, technical assistance and product development advice. Today, EPS experts and R&D personnel work with several companies to develop customized mixes of high-quality SiC.

EPS owns state-of-the-art equipment needed to mix, classify and pack SiC to exact customer requirements. EPS also has laboratory equipment to carry out XRD analyses to provide chemical and structural information, as well as physical testing devices (PSD, BET, density, etc.), ensuring accurate measuring of particle sizes, moisture and pH. Customers are therefore assured of getting the right product in the right size packaging and at the right time.

At the processing stage, customers are then fully supported by experienced industry specialists to get the results they require in their very competitive businesses. The highly competent staff of EPS provides full customer services, technical assistance and product development advice and support.

Sustainability at Elkem

To learn more about our sustainability initiatives, check our webpage.

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