Some properties and uses of silicon carbide ceramics

Silicon carbide ceramics is a material with high strength, high thermal conductivity, acid and alkali corrosion resistance, it can adapt well to the external environment in the process of use, the industry is considered to be the best corrosion-resistant heat exchanger material. Ordinary ceramic materials in 1200 ~ 1400 ℃ when the strength will be significantly reduced, and silicon carbide ceramics in 1400 ℃ when the bending strength is still maintained at a high level of 500 ~ 600MPa, and its operating temperature up to 1600 ~ 1700 degrees Celsius.

Silicon carbide ceramics is not only low density, and very high hardness, is one of the hardest ceramic materials. Its material properties can remain unchanged at temperatures up to 1400°C. The material has a high modulus (Young’s modulus). The high Young’s modulus (>400 GPa) ensures dimensional stability under high pressure. It is also toxicologically safe and can also be used in the food industry. In addition, SiC materials have
excellent thermal conductivity, low thermal expansion and are very resistant to acids and alkalis.

The characteristics of SiC ceramics mainly include: reusable, does not cause material waste, advocating sustainable development; chemical corrosion resistance, can be used in highly corrosive chemical plants, etc., in the temperature range of -70 ℃ to ＋260 ℃ corrosion resistance, oxidation and corrosion resistance is very high, long service life, lower maintenance costs and longer uptime; high temperature resistance, 1800 ℃ normal use, and will not be used in the food industry. 1800 ℃ normal use, and will not be melted damage, stability; high thermal conductivity, ultra-high temperature stability, stable structural performance. Its thermal conductivity is second only to beryllium oxide ceramics in ceramics.

Why do more chemical companies choose to use silicon carbide as a heat transfer material rather than beryllium oxide? The reason is very simple – as we all know, although beryllium oxide ceramics are not toxic, but its raw material BeO is a toxic substance, in the manufacturing and use of the process of BeO dust and vapors on human health will cause serious damage to the toxicity of its protective measures taken by an additional increase in the cost, so that the original price of BeO ceramics become more expensive. Comprehensive comparison, the cost-effectiveness of silicon carbide appears to be more cost-effective, not only good performance, the raw material is also harmless to human health and cheaper, more suitable for high-volume production operations.

Silicon carbide ceramics are used in a wide range of applications in aerospace, energy extraction, the electronics industry and mechanical construction, as well as in fire resistance, for example in the following areas:

Rotary ball and roller bearings
Heat- and wear-resistant engine components
Industrial and chemical ball valve fittings
Valves, rocker gaskets, sealing surfaces
Induction heating coil supports
Turbine blades, vanes, buckets
Welding and brazing fixtures
Heating element components
Stationary and mobile turbine components
Seals, bearings, pump vanes
Wear plates and ballistic armor
Kilns and heat exchangers
Semiconductor wafer processing equipment