The steel structure is usually sprayed with zinc or aluminum, and the heavy-duty corrosion coating forms a long-term corrosion-resistant structure, or the supporting heavy-duty corrosion coating is used for protection.Zinc and aluminum are very resistant to atmospheric corrosion.Spraying zinc or aluminum on steel components, zinc and aluminum are negative potential and form sacrificial anode protection effect on steel, so that steel is basically protected.At present, aluminum spray coating is used to prevent the corrosion of industrial atmosphere and marine atmosphere. Its characteristics are as follows:

(1) The bonding force between aluminum spraying coating and steel substrate is firm, the coating life is long, and the long-term economic benefit is good;

(2) Flexible technology, suitable for long-term protection of important large-scale and difficult to maintain steel structures, and can be used for site construction;

(3) The service life of the coating can be greatly extended by spraying zinc or aluminum coating and sealing with anti-corrosive coating. From the theoretical and practical application results, the coating of spraying zinc or aluminum is the best bottom layer of anti-corrosive coating.The protective life of composite coating of metal spraying layer and anti-corrosive coating is longer than the sum of metal spraying layer and anti-corrosive coating, which is several times of that of single coating.

The heavy-duty long-term anti-corrosive coating is composed of primer, intermediate coat and finish coat.

Considering the long-term economy, spraying aluminum coating is the most economical, but the investment is large, and the coating with good construction can be maintained in 10 years.Epoxy zinc rich primer + epoxy micaceous iron intermediate paint and acrylic polyurethane long-term protection system have better economy.