2025-07-23    274

Zinc and aluminum, having a more negative electrochemical potential than steel, form sacrificial anodes with the steel structure, thereby providing cathodic protection to the base steel. Currently, aluminum spraying coatings are used to protect against corrosion in industrial and marine atmospheres. This method for steel structures has the following characteristics:

(1) The aluminum spraying coating exhibits strong adhesion to the steel substrate, has a long service life, and offers good long-term economic benefits.
(2) The process is flexible, suitable for the long-term protection of important large-scale and difficult-to-maintain steel structures, and allows for on-site application.
(3) Applying a sealing coat of anti-corrosive paint over the zinc or aluminum sprayed coating can significantly extend the coating system's service life. Both theoretically and in practical application, zinc or aluminum sprayed coatings serve as the optimal primer layer for anti-corrosive paints. The protective life of the composite coating system (metal spray coating + paint coating) exceeds the sum of the individual lives of the metal spray coating and the paint coating, amounting to several times the service life of a single paint coating system.

Heavy-duty long-term anti-corrosive paint systems typically consist of a primer, intermediate coat, and topcoat.

Considering long-term economics, the aluminum spraying coating is the most economical option, although it requires a higher initial investment. A well-applied coating can be maintenance-free for up to 10 years. The long-term protection system comprising an epoxy zinc-rich primer + epoxy mica iron oxide intermediate coat + acrylic polyurethane topcoat offers excellent cost-effectiveness.

For steel structures, zinc or aluminum spraying is commonly used, combined with heavy-duty anti-corrosive paints to form a long-lasting anti-corrosion system. Alternatively, a matched system of heavy-duty anti-corrosive paints can be applied for protection. The metals zinc and aluminum possess excellent resistance to atmospheric corrosion. Therefore, zinc or aluminum is sprayed onto steel components.