Silicon Carbide Ceramic Tubes and Thermocouple Protection Tubes

Silicon carbide (SiC) ceramic tubes are tubular components made from silicon carbide powder through molding and high-temperature sintering (e.g., pressureless sintering or reaction sintering). Silicon carbide ceramic tubes are not ordinary tubes; rather, they are advanced industrial ceramic materials with exceptional performance, providing high-performance solutions for demanding working conditions.

Silicon carbide ceramics combine several extreme properties, making them irreplaceable in numerous applications:

1. Extreme High-Temperature Resistance:
They maintain exceptional strength and hardness even in temperatures exceeding 1600°C, exhibit excellent oxidation resistance, and can even temporarily reach operating temperatures of 1650°C. This is one of their most significant advantages.

2. Excellent Wear Resistance:
With an extremely high hardness (Mohs hardness of 9.2-9.5, second only to diamond and boron carbide), their wear resistance far exceeds that of alumina ceramics, making them ideal for conveying ultra-hard, ultra-fine, abrasive media.

3. Excellent Thermal Conductivity:
This is one of the key differences from alumina ceramics. Silicon carbide is an excellent thermal conductor, with a thermal conductivity far exceeding that of most ceramics and metals. This makes it ideal for applications requiring rapid heat transfer, such as heat exchangers and kiln furniture.

4. Excellent Corrosion Resistance:
It resists corrosion from most acids (including boiling hydrochloric acid, sulfuric acid, and nitric acid), alkalis, and saline solutions, surpassing alumina ceramics in overall corrosion resistance. However, it will corrode in strong oxidizing acids (such as hydrofluoric acid and mixtures of nitric and hydrofluoric acids).

5. High Mechanical Strength:
It has very high compressive and flexural strengths, with minimal strength loss at high temperatures.

6. Good Thermal Shock Resistance:
Thanks to its high thermal conductivity and low coefficient of thermal expansion, it can withstand rapid temperature changes (such as rapid cooling and heating) without cracking, far surpassing alumina ceramics.

The exceptional performance of silicon carbide ceramic tubes has led to their application in the following high-end applications:
1. High-temperature kilns and heat treatment industries:

• Kiln furniture: Used as rollers in roller hearth kilns, they offer excellent load-bearing properties, resist deformation at high temperatures, and are resistant to thermal shock. They are key components for the sintering of high-end ceramics and lithium battery materials.
• Beams and brackets: Support components for setters.

2. High-efficiency heat exchangers:

• Utilizing their high-temperature resistance, corrosion resistance, and high thermal conductivity, silicon carbide heat exchanger tube bundles are used to recover heat from high-temperature exhaust gases in industries such as chemical, metallurgical, and glass. They can also treat corrosive flue gases with exceptional efficiency.

3. Demanding Wear-Resistant and Corrosion-Resistant Conveying:

• Conveying extremely sharp and hard particulate materials (such as silicon carbide powder, diamond powder, ore slurry, etc.).
• Chemical processes experience extreme conditions of high temperature, corrosion, and wear.

4. Environmental Protection and Power Industry:

• Desulfurization spray guns: Used in power plant flue gas desulfurization (FGD) systems to spray limestone slurry, offering corrosion, wear, and thermal shock resistance.
• Dust removal system piping.

5. Semiconductor Industry:

• Used as thermal insulation components and carriers in high-purity silicon crystal growth furnaces (such as zone furnaces), they are highly suitable for high-purity, high-temperature resistance, and the introduction of no metal contamination.