Many new materials have been developed, but steel remains the principal construction material for automobiles, appliances, and industrial machinery. Because of steel's vulnerability to attack by aggressive chemical environments or even from simple atmospheric oxidation, coatings are necessary to provide various degrees of protection. They range from hot-dipped and electroplated metals to tough polymers and flame-sprayed ceramics. In general, corrosive environments contain more than one active material, and the coating must resist penetration by a combination of oxidizers, solvents, or both. Thus, the best barrier is one that resists "broadband" corrosion. Physical integrity of the coating is as important as its chemical barrier properties in many applications. For instance, coatings on impellers that mix abrasive slurries can be abraded quickly; coatings on pipe joints will cold-flow away from a loaded area if the creep rate is not low; and coatings on flanges and support brackets can be chipped or penetrated during assembly if impact strength is inadequate. Selecting the best coating for an application requires evaluating all effects of the specific environment, including thermal and mechanical conditions. One of the most common and inexpensive protection methods for steel is provided by zinc. Zinc-coated, or galvanized, steel is produced by various hot-dipping techniques, but more steel companies today are moving into electrogalvanizing so they can provide both. Oxidation protection of steel by zinc operates in two ways -- first as a barrier coating, then as a sacrificial coating. If the zinc coating is scratched or penetrated, it continues to provide protection by galvanic action until the zinc layer is depleted. This sacrificial action also prevents corrosion around punched holes and at cut edges. The grades of zinc-coated steel commercialized in recent years have been designed to overcome the drawbacks of traditional galvanized steel, which has been difficult to weld and to paint
Products & Services
Galvanizing services involve the application of a protective zinc coating on metals such as steel or iron. The zinc layer forms a barrier that protects the underlying steel by providing sacrificial or galvanic corrosion protection on the steel surface.
Coating services apply a thin layer of material onto parts or products provided by a client. These services are used by companies that do not have coating technology and equipment in house.
Corrosion Protection Services
Corrosion protection services mitigate environmental or chemical attack through the application or installation of coatings, liners, cathodic protection, sacrificial anodes, and corrosion inhibitors.
Industrial coatings are thin films deposited upon materials to add or enhance desired properties, such as color, conductivity, corrosion resistance, etc.
Architectural coatings include paints, sealers, and specialty coatings for floors, roofs, walls, ceilings, decks, pavement, walkways, concrete surfaces, and other building and construction applications.
Topics of Interest
4.3.5 APPLICATION OF PRINCIPLES OF GALVANIC CORROSION
A Non-metallic Conductors
Many non-metallic materials are cathodic to metals and alloys. For example, impervious graphite used in heat...
New corrosion-control coatings are simple to apply and better withstand harsh environments than zinc phosphating. Improved protection against rust and corrosion is one reason automakers have been able...
Rust preventative coatings are designed to minimize rust or iron alloy corrosion when applied directly to ferrous metal such as carbon or alloy steels. They protect against rust by preventing moisture...
14-9 SURFACE COATING
Surface coating should be chosen with regard to the application it has to serve, along with a consideration for the basic metal it has to cover. Some coatings are used as a...
Zinc, a crystalline metal with moderate strength and ductility, is seldom used alone except as a coating. In addition to its metal and alloy forms, zinc also extends the life of other materials such...