What is zinc-aluminum composite coating

       Zinc-aluminum composite coating refers to a double-layer coating system of zinc and aluminum. The zinc coating is sprayed on the bottom layer in direct contact with the steel substrate, and the aluminum coating is sprayed on the outside. The purpose of the application of this two-layer coating system is to overcome some of the shortcomings of the single coating system, and can well play the respective advantages of the two coatings. Aluminum coating has better mechanical properties, stable oxide film surface, so it has longer corrosion resistance life under many conditions. However, the disadvantage of aluminum coating is that it cannot provide sufficient cathodic protection to the steel substrate under some circumstances. Steel components that have just been sprayed with aluminum may develop appearance-impairing rust on the surface shortly after they have been placed in a humid atmosphere. The application of zinc-aluminum composite coating can solve this problem very well. The zinc coating as the bottom layer not only provides effective cathodic protection, but also increases the reliability of the bonding between the aluminum coating and the steel components. Because zinc coatings require less surface preparation for steel substrates than aluminum coatings, reliable bonding of zinc coatings can be achieved even with slightly lower blast quality surfaces.



There are many applications of this zinc-aluminum composite coating. For example, this anti-corrosion coating system is used on naval vessels in the United Kingdom, Australia and New Zealand. It has also been used in water conservancy facilities and steel bridges in my country.