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Definition of Metalizing
Metalizing is a process by which a metallic coating is deposited onto a surface. Aluminum or zinc is sprayed onto a blast cleaned steel surface (SSPC SP5) to form a protective coating. The metalized coating is both a barrier and a galvanic coating, which protects steel for 30 years or longer.
The American Welding Society (AWS) defines metalizing (thermal spraying) as: "A group of processes in which finely divided metallic or nonmetallic surfacing materials are deposited in a molten or semi-molten condition on a substrate to form a spray deposit."
The National Metalizing Association™ explains that metalizing is a process in which a wire is heated to its melting point and the molten metal is sprayed by compressed air to form a protective coating. The heat source for melting the wire may be either burning gas (flame spray), or electric arc (twin wire electric arc spray).
Sealers and paint topcoats may be applied over the sprayed metal. The combined materials protect the underlying steel better than any of the materials used separately. The sealed-sprayed metal is often the most cost-effective combination of materials. Paint topcoats may be used for additional corrosion resistance, abrasion resistance or for aesthetic reasons. [For more information, see section Specification, Sealing and AWS 19 Year Report, Conclusions.]
Paints just do not last long enough to compete with metalizing. Paint manufacturers cannot point to a single paint product in continuous use for 80+ years with the consistent and highly effective results of metalizing. Instead, paint manufacturers have to predict service lives for new paint products based on what may be questionable test information. For more on this subject, see "Paint's Perpetual Problems".
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