Corundum Vs Corundum Mullite Bricks Hightemperature Performance Compared

In high-temperature industrial environments, the selection of refractory materials is critical. Corundum brick and corundum-mullite brick stand out as two premium refractory materials, favored for their exceptional compressive strength and wear resistance at elevated temperatures. However, these materials exhibit significant differences in composition, physical properties, and application scenarios. This analysis provides engineers and material specialists with comprehensive insights to facilitate informed decision-making.

Corundum brick primarily consists of high-purity aluminum oxide (Al₂O₃), with corundum serving as its key crystalline phase. Manufacturers strictly control raw material purity to minimize impurities like free silicates. The material's dense crystalline structure, formed during sintering, delivers outstanding mechanical strength and durability under extreme thermal and mechanical stress.

This composite material combines corundum, mullite (3Al₂O₃·2SiO₂), and minor alumina components. Mullite's inclusion enhances thermal shock resistance and high-temperature stability. The manufacturing process requires precise control of material ratios and sintering parameters to achieve optimal microstructure distribution, resulting in superior performance characteristics.

Corundum brick demonstrates higher density (3.1-3.8 g/cm³) compared to corundum-mullite brick (2.9-3.2 g/cm³), reflecting greater material compactness and reduced porosity. This density difference directly influences mechanical strength and erosion resistance.

At 1600°C, corundum brick maintains compressive strength exceeding 120 MPa, outperforming corundum-mullite brick (80-90 MPa). This advantage stems from corundum brick's higher crystalline phase content and denser microstructure.

Corundum brick's exceptional wear resistance, derived from its high corundum content (second only to diamond in hardness), makes it ideal for abrasive environments. While corundum-mullite brick offers good wear resistance, its performance is slightly inferior due to mullite's lower hardness.

Both materials exhibit excellent thermal stability, maintaining structural integrity across 1400°C-1800°C operating ranges without deformation or degradation.

Corundum brick shows marginally lower thermal expansion (6.0×10⁻⁶/°C at 900°C) than corundum-mullite brick (7.0×10⁻⁶/°C), making it preferable for applications requiring minimal dimensional changes during thermal cycling.

• High-temperature furnace linings in metallurgical processes
• Refractory linings for rotary kilns and vertical furnaces
• Precision casting molds for dimensional accuracy
• Aluminum electrolysis cell linings

• Acidic environments in steel manufacturing
• High-temperature electrolysis equipment
• Ceramic kiln furniture and thermal insulation components

Material selection should consider:

• Maximum operating temperature requirements
• Exposure to corrosive media (acids, alkalis, molten slag)
• Mechanical stress conditions (static/impact loading, thermal stress)
• Lifecycle cost analysis (initial cost vs. maintenance requirements)

Corundum brick is generally preferred for extreme temperature and mechanical stress conditions without significant corrosion, while corundum-mullite brick excels in acidic environments or situations requiring enhanced thermal shock resistance.

Both refractory materials offer distinct advantages tailored to specific operational demands. Corundum brick delivers superior mechanical strength and wear resistance, while corundum-mullite brick provides better corrosion resistance and thermal shock tolerance. Future research should focus on microstructural optimization and cost-effective production methods to meet evolving industrial requirements.