March 9, 2016
Metallizing and hot-dip galvanizing are two zinc-based coatings that protect the steel substrate by physical barrier and cathodic protection. However, these two coatings are significantly different. Metallizing relies on a mechanical bond between the zinc and the surface of the steel substrate to form a protective coating. Because of this mechanical bond, the surface preparation is critical to performance. Hot-dip galvanizing is a total immersion process where the steel element is dipped into a bath of molten zinc. Unlike metallizing, galvanizing metallurgically bonds the zinc to the steel substrate making it a part of the steel, not a coating. The size and shape of a steel member that can be galvanized is determined by the size of the kettle containing the molten zinc. For practical reasons, primary bridge elements such as girders are often metallized and connected to secondary components such as cross frames that can be hot-dip galvanized. Tomorrow: What are the advantages of metallizing? For more information, view our video on metallizing and visit the Painting and Metallizing section of our website. For any questions regarding this post, contact us.
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