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Metposite panels are
formed from Zincalume® or Galvalume® steel. Both have a metallic
coating applied by a continuous coating process whereby properly cleaned
low-carbon, cold-rolled sheet steel is dipped into a molten
aluminum-zinc bath.
The alloy bath temperature is around 600C, and the coating is solidified
very rapidly to obtain a fine-grain microstructure with enhanced
corrosion resistance, compared to the pure zinc coating (galvanized
coating) or pure aluminum.
The
Galvalume®
coating contains 55% aluminum, 43.5% zinc, and
1.5% silicon.
The result is a highly corrosion-resistant sheet steel that
delivers the best protective features characteristic of aluminum and
zinc: the barrier protection and long life of aluminum plus the
sacrificial or galvanic protection of zinc at cut or sheared edges
In addition to forming a
physical barrier against corrosion, zinc, applied as a hot-dip
galvanized coating catholically protects exposed steel. Zinc has a
self-healing mechanism in it. The zinc coating sacrifices itself slowly
by galvanic action to protect the base steel. This sacrificial action
continues as long as any zinc remains in the immediate area.
In simple terms the edges will not rust.
The silicon is introduced primarily to assist in the formation of
a thin layer of inter-metallic compound between the coating and base
metal, providing coatings with good adhesion.
Hot-dip galvanized steel
will last very well in most environments. It is not uncommon for
galvanized steel to last more than 70 years. Hot-dip galvanized steel
has been effectively used for more than 150 years. The value of hot-dip
galvanizing stems from the relative corrosion resistance of zinc.
In addition to all the protective quality, it has excellent
forming capabilities. Therefore, no damage or compromise of the metal’s
strength or corrosion protection occurs during the forming of the
panels.
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