Advantages of Nitride Bonded Silicon Carbide Ceramic Stalk Tubes

Advantages of Nitride Bonded Silicon Carbide(NSiC) Ceramic Stalk Tubes

1. **Excellent High - Temperature Performance**    - **High - Temperature Resistance**NSiC riser tubes can withstand extremely high temperatures. In the melting and casting processes of metals such as aluminum alloys, they can operate stably in a high - temperature environment above 1400°C. This is because both silicon nitride and silicon carbide have high melting points. The melting point of silicon nitride is approximately 1900°C, and that of silicon carbide is as high as around 2700°C. This high - temperature stability enables the lifting tubes to adapt to various high - temperature melting scenarios, effectively preventing problems such as material softening, deformation, or even melting at high temperatures.    - **Good Thermal Shock Resistance** During the casting process, the lifting tubes frequently experience temperature changes. For example, when the molten metal rises and falls through the lifting tube, the temperature of the inner and outer walls of the tube changes rapidly. NSiC riser tubes have excellent thermal shock resistance. This is due to the relatively low thermal expansion coefficients of silicon nitride and silicon carbide, and the ceramic structure formed by their combination can effectively relieve thermal stress. This thermal shock resistance ensures that the lifting tubes do not crack under repeated temperature impacts, thus greatly extending their service life.2. **Good Chemical Stability**    - **Strong Corrosion Resistance**During the metal melting process, the lifting tubes come into contact with various chemical substances, such as molten metals, fluxes, and protective gases. NSiC riser tubes have good corrosion resistance to many molten metals (such as aluminum alloys, magnesium alloys, etc.) and some corrosive fluxes. Taking aluminum alloy casting as an example, the aluminum liquid has certain chemical activity at high temperatures. However, the silicon nitride - bonded silicon carbide ceramic material can resist the erosion of the aluminum liquid and does not react chemically with it, thus ensuring the structural integrity of the lifting tube and the quality of the cast metal.    - **Good Oxidation Resistance**In a high - temperature and oxygen - containing environment, many materials are prone to oxidation reactions. However, NSiC riser tubes have good oxidation resistance. This is because a dense oxide protective film forms on its surface, preventing further oxygen penetration into the material. For example, in the environment of a high - temperature foundry workshop, even if exposed to air for a long time, the performance of the lifting tube will not significantly decline due to oxidation, and it can maintain good working conditions.3. **Superior Mechanical Properties**    - **High Strength**NSiC riser tubes have high mechanical strength. They can withstand the gravity and pressure of the molten metal, as well as external forces during transportation and installation. This high strength ensures that the lifting tubes do not easily crack or be damaged during use. For example, in large - scale casting equipment, when the lifting tube needs to transport a large amount of high - density molten metal, its high - strength characteristics can ensure the normal operation of the lifting tube without deformation or damage due to the pressure of the molten metal.    - **High Hardness**The high hardness of the lifting tubes gives them good wear resistance. During the scouring of the molten metal and contact with other equipment components, the surface of the lifting tube is not easily worn. This helps to maintain the dimensional accuracy and surface quality of the lifting tube, thereby ensuring the stable transportation of the molten metal and the precise control of the casting process.4. **Other Advantages**    - **Long Service Life**Combining the above advantages of high - temperature performance, chemical stability, and mechanical properties, the service life of NSiC riser tubes is much longer than that of traditional material (such as cast iron) lifting tubes. This can reduce the equipment replacement frequency and costs of enterprises and improve production efficiency.    - **Low Contamination to Molten Metal**Due to its good chemical stability, during the contact with the molten metal, it will not release impurities or react chemically with the molten metal to produce harmful components. Therefore, it has a very low degree of contamination to the molten metal, effectively ensuring the purity and quality of the cast metal.

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