What is Silicon Carbide Ceramic?

Silicon carbide ceramics, commonly known as SiC ceramics, are a versatile material with unique properties and a wide range of applications in various industries.

Material composition of SiC ceramics

Silicon carbide ceramics are mainly composed of SiC powder, which has two main crystal structures: cubic (β-SiC) and hexagonal (α-SiC). These powders are mixed with an appropriate ceramic binder and then molded and sintered to form the final ceramic material. SiC, also known as silicon carbide, is a compound with strong covalent bonds, making it extremely hard and durable.

Main properties of SiC ceramics include:

‌● High melting point‌: Silicon carbide has an extremely high melting point and can withstand high temperature environments. The specific melting point data may vary from different sources, but it is generally believed to be around 2100℃ or higher‌. ‌High hardness and high strength‌: The Mohs hardness of silicon carbide is about 9.5, and the Vickers hardness is about 2800-3300HV, which is second only to diamond and boron nitride, and has extremely high wear resistance‌. At the same time, its strength is also very high and can withstand large mechanical stress‌.

‌● ‌High thermal conductivity‌: The thermal conductivity of silicon carbide ceramics is about 80-220W/(m·K), and even in some pressureless sintered silicon carbide ceramics, the thermal conductivity can be as high as 100~120W/m·k, which is much higher than traditional alumina ceramics and aluminum nitride ceramics‌. This enables silicon carbide ceramics to quickly conduct and disperse heat in high temperature environments, improving the stability and life of the equipment.

‌‌● Good electrical insulation‌: Silicon carbide ceramics have good electrical insulation, with a breakdown voltage of up to 30kV/mm, which can effectively prevent arc discharge and leakage‌.

‌‌● Chemical stability‌: Silicon carbide is resistant to acid and alkali, not easy to corrode, and can work stably in a variety of chemical media‌.

Forming and sintering methods

There are many ways and categories for forming silicon carbide ceramics, mainly including hot pressing sintering, pressureless sintering, reaction bonding, recrystallization sintering, microwave sintering and spark plasma sintering. Different sintering methods will lead to different performance differences of silicon carbide materials.

‌‌‌● Pressureless sintered silicon carbide (SSiC): Made from pure silicon carbide powder and oxide-free sintering aids at a high temperature of about 2000°C using a series of forming methods (including dry pressing and extrusion).

‌‌‌● Reaction sintered silicon carbide (SiSiC): Premix an appropriate amount of carbon-containing material in silicon carbide powder, and use the high-temperature reaction of carbon with residual silicon in silicon carbide powder to synthesize a new type of silicon carbide to form a dense silicon carbide ceramic. The reaction sintering process has the advantages of low sintering temperature, short sintering time, and near net shape. It is the most effective method for preparing large-sized and complex-shaped silicon carbide ceramics.

Common Problems in Silicon Carbide Ceramic Processing

Despite its excellent properties, silicon carbide ceramics still face significant challenges during processing for the following reasons:

‌‌‌● High hardness‌: The extremely high hardness of silicon carbide makes it difficult to cut or grind, causing traditional metal tools to wear out quickly.

‌‌‌● Brittleness‌: Unlike metals, silicon carbide ceramics are brittle and easily break under impact or pressure, complicating traditional cutting methods.

‌‌● Thermal conductivity‌: While silicon carbide is useful in many applications, its high thermal conductivity can concentrate heat during processing, causing the material to crack or deform.

‌‌‌● Chemical stability‌: Silicon carbide's resistance to most chemicals complicates the selection of tools and coolants, and specialized materials may be required to avoid adverse reactions.

Specific Application Scenarios of Silicon Carbide Ceramic (SiC Ceramic)‌

1. ‌Semiconductor and Electronics Industry‌

‌‌‌● Key Components of Semiconductor Equipment‌: SiC ceramics are used to manufacture grinding discs, suction cups, wafer boats and fixtures for semiconductor equipment. Due to their high purity, chemical corrosion resistance and high precision, they are suitable for chip manufacturing and packaging processes‌. ‌

‌‌● High-frequency power devices‌: As substrates or packaging materials for high-frequency power devices, the high thermal conductivity and high-temperature resistance of SiC ceramics can improve the performance of wireless communications, radars and other equipment.

‌‌‌● Power electronic components‌: Used to manufacture power modules, capacitors and inductors, they can maintain stable operation in high-temperature and high-voltage environments.

2. ‌Aerospace and high-temperature fields‌ ‌

‌‌● Engine high-temperature components‌: SiC ceramics are used in rocket engine combustion chambers, turbine blades and guide vanes to reduce weight while improving high-temperature resistance (>1600℃).

‌‌‌● Thermal protection system‌: As a thermal protection material for spacecraft, it can resist extreme high temperatures and airflow shocks during high-speed flight.

‌‌● ‌High-temperature kiln furniture‌: In the metallurgical and ceramic industries, kiln furniture such as SiC beams and rollers can withstand high-temperature environments (such as 1300-1600℃) for a long time, improving production efficiency.

3. ‌Chemical and corrosion-resistant environments‌ ‌

‌‌● Desulfurization nozzles and reactors‌: The acid and alkali resistance of SiC ceramics makes it an ideal material for desulfurization systems and chemical reactors, with a service life far exceeding that of metal parts.

‌‌● Magnetic pumps and shielded pumps: Key sealing components such as sealing rings and bearings used to transport corrosive media to avoid leakage and wear.

4. Machinery and energy fields

‌‌● High-performance seals: SiC ceramic sealing rings perform well under harsh conditions (such as high pressure and high speed) and are widely used in petrochemical and mechanical sealing systems.

‌‌● Nuclear energy and new energy: As a nuclear reactor structural material or fuel cell electrode, SiC's radiation resistance and high temperature resistance can improve equipment safety.

‌‌● Solar energy and heat exchangers: Used for solar cell encapsulation or high-temperature heat exchangers to improve energy conversion efficiency and weather resistance.

5. Traditional industries and special purposes

‌‌● Abrasives and processing tools: SiC grinding wheels, abrasive belts, etc. are used for precision processing of metals, glass and ceramics, especially for grinding cemented carbide and optical glass.

‌‌● Refractory materials and metallurgy: As blast furnace linings, iron ladles and electrolytic cell materials, they reduce the erosion of molten metal on equipment.

‌‌● ‌Automotive Industry‌: Used in the manufacture of brake systems, turbochargers and engine components to improve wear resistance and thermal efficiency‌.

Why choose Veteksemicon's silicon carbide ceramics?

• Baffles & holders
• Injectors
• Liners & process tubes
• Silicon Carbide Cantilever Paddles
• Wafer boats and pedestals

If you are interested in our sic ceramics products, please contact us as soon as possible. We sincerely look forward to being your long-term partner in China.