Aluminized zinc coil is a high-performance metal material made from cold-rolled steel sheet as the base material, with an aluminum-zinc alloy coating formed on the surface through a hot-dip galvanizing process. It combines the cathodic protection characteristics of galvanized steel sheet with the high-temperature resistance and corrosion resistance of aluminized steel sheet, and is widely used in construction, home appliances, industrial equipment, and other fields.
Basic Composition and Coating Components
The core of aluminized zinc coil lies in its coating, typically composed of 55% aluminum, 43.4% zinc, and 1.6% silicon (by weight). This ratio is widely adopted and referred to as the "55% aluminum-zinc-silicon alloy coating."
- Aluminum: Forms a dense oxide film, providing excellent corrosion resistance and heat resistance;
- Zinc: Protects the steel base through sacrificial anode action, especially exhibiting self-healing ability at cuts or scratches;
- Silicon: Improves coating fluidity and adhesion, enhancing uniformity.
This composite structure exhibits a layered microstructure: an upper aluminum-rich phase provides a protective barrier, while a lower zinc-rich zone provides electrochemical protection, thus achieving a dual anti-corrosion mechanism.
Core Performance Characteristics
- Superior Corrosion Resistance: Under the same conditions, the corrosion resistance life of aluminized zinc coils can be 2–3 times that of ordinary galvanized sheets, and under certain conditions, even up to 36 times. It exhibits stability in environments such as acid rain, humidity, and industrial atmospheres, making it suitable for C5-level highly corrosive environments, such as coastal factories and chemical facilities.
- Excellent Heat Resistance: It can withstand temperatures above 300℃ for extended periods and up to 600℃ for short periods, making it suitable for high-temperature components such as chimneys, ovens, lighting fixtures, and exhaust pipes.
- High Heat Reflectivity: Its heat reflectivity is approximately twice that of ordinary galvanized sheets, effectively reflecting solar radiation and reducing interior building temperatures. It is widely used in energy-saving applications such as roofs and insulation panels, helping to reduce air conditioning energy consumption.
- Excellent Heat Reflectivity: It has approximately twice the heat reflectivity of ordinary galvanized sheets, effectively reflecting solar radiation and reducing interior building temperatures. It is widely used in energy-saving applications such as roofs and insulation panels, helping to reduce air conditioning energy consumption.
- Excellent processability and paintability: It retains the formability of cold-rolled steel, allowing for bending, stamping, shearing, and other processing. Its smooth surface makes it easy to paint or coat, making it suitable for producing color-coated sheets.
- Economic advantages: Because aluminum has a lower density than zinc, aluminum-zinc coated sheets cover approximately 3% more area than galvanized sheets of the same weight, reducing material costs per unit area and improving economic efficiency.
