Aluminized zinc-coated steel sheet exhibits significantly superior corrosion resistance compared to traditional galvanized steel sheet, making it a widely used high-performance anti-corrosion material in industrial and construction fields.
Core Advantages in Corrosion Resistance
- Long Service Life: Under the same environmental conditions, the service life of aluminized zinc-coated steel sheet can reach over 25 years, 3 to 6 times that of ordinary galvanized steel sheet.
- Outstanding Performance in Salt Spray Environments: In salt spray tests, the rust area of aluminized zinc-coated steel sheet is only 1/4 that of galvanized steel sheet, and its corrosion resistance is 2 to 6 times that of the latter. Its corrosion resistance is particularly stable in coastal, humid, or industrial atmospheric environments.
Composite Anti-corrosion Mechanism
- Aluminum Barrier Protection: Aluminum rapidly oxidizes on the surface to form a dense alumina film, effectively blocking the penetration of moisture and oxygen, preventing further corrosion of the substrate.
- Zinc Sacrificial Protection: At cuts or damaged areas, zinc preferentially corrodes, protecting the exposed steel substrate through the "sacrificial anode" effect.
This dual protection mechanism of "aluminum barrier + zinc sacrifice" enables galvanized steel sheets to maintain excellent corrosion resistance even under complex working conditions.
Key Factors Affecting Corrosion Resistance
- Coating Composition: The standard coating consists of 55% aluminum, 43.4% zinc, and 1.6% silicon. This ratio optimizes the balance between corrosion resistance and processability.
- Coating Thickness: Common coating weights include 80g/m², 100g/m², 120g/m², and 150g/m². The thicker the coating, the stronger the corrosion resistance. AZ150 (150g/m² total weight on both sides), commonly used in construction, is sufficient for most moderately corrosive environments.
Operating Environment
- Dry Environment: Almost no corrosion occurs; performance is extremely stable.
- Humid/Marine Climate: Thanks to the dense oxide film of aluminum, it effectively resists salt spray and water vapor corrosion.
- Industrial Atmosphere: Good resistance to acidic gases and particulate matter.
- Alkaline environment: Compared with ordinary aluminum zinc plating, aluminum magnesium zinc plating (such as SD series) performs better under higher pH conditions.
