Industrial Heat Treatment Muffle Furnace U-Shaped Silicon Carbide Heating Elements

Physicochemical Properties of Silicon Carbide Rods:

Element Texture: Hard and brittle, resistant to rapid cooling and heating, not easily deformed at high temperatures. Other physical properties are as follows:

Thermal Conductivity: 20 cal/m·h·°C

Linear Expansion Coefficient: 5×10⁻⁶ (m/°C)

Chemical Properties: Good chemical stability, strong resistance to acids. Alkaline substances can erode it under high-temperature conditions.

When silicon carbide rod elements are used long-term above 1000°C, they react with oxygen and water vapor as follows:

① SiC + 2O₂ → SiO₂ + CO₂ ② SiC + 4H₂O = SiO₂ + 4H₂ + CO₂

This causes the SiO₂ content in the element to gradually increase, and the resistance slowly rises, leading to aging. Excessive water vapor promotes the oxidation of SiC. The H₂ produced by reaction ② combines with O₂ in the air to form H₂O, creating a vicious cycle and reducing the element's lifespan. Hydrogen (H₂) can reduce the mechanical strength of the element. Nitrogen (N₂) can prevent SiC oxidation below 1200°C but reacts with SiC above 1350°C, causing SiC decomposition. Chlorine (Cl₂) can completely decompose SiC.