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Optional Galvanized Trailer
SHINY VS. MATTE GRAY
HOT-DIP GALVANIZED STEEL
| A proven cost-effective and durable corrosion protection system, the hot-dip galvanizing process entails cleaning steel in a series of chemical solutions and then immersing the steel in a bath of molten zinc metal. During galvanizing, the molten zinc naturally reacts with the surface of the steel to form a series of zinc-iron alloy layers that protect the underlying steel from corrosive attack. Figure 1 is a photomicrograph of a cross-section of a galvanized coating. |
| The first zinc-iron alloy layer, the Gamma layer, is approximately 75% zinc and 25% iron. The next layer, the Delta layer, is approximately 90% zinc and 10% iron. The third layer, the Zeta layer, is approximately 94% zinc and 6% iron. The last layer, which forms as the material is withdrawn from the zinc bath, is approximately 100% pure zinc. |
Newly galvanized steel with the typical pure outer zinc layer is highly reflective. In the absence of the pure zinc layer, intermetallic layers are exposed and reflectivity is greatly reduced. This reflectivity change will also happen naturally, over time, as the zinc coating weathers and zinc oxide and carbonate films form. It is important to note that corrosion prevention is not dependent upon whether the coating is shiny or matte.
Information courtesy of the American Galvanizers Association. |
FIGURE 1
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