It's no secret that annual losses due to corrosion of 10-15% of the total steel produced. In some cases, the metal structure or its separate parts can simply be replaced with time. However, such a procedure cost to the customer in a rather tidy sum. Moreover, in most cases, the design simply can not be replaced or its installation is expected that it should last for 20-30 years without a substantial overhaul. Most of such a problem faced in chemical industries or areas with a fairly aggressive environment – for example, if the object is located on the coast.
In such cases, to save the situation may be the optimal selection of corrosion coatings. Anticorrosive materials and coatings designed to prolong the life of various structures and protect them from aggressive environmental influences. Are useful for the effective protection corrosion materials for epoxy or polyurethane with special fillings. Type of binder and filler type, suitable for this environment are well documented in the standard ISO-12944. There are all types of environmental divided into groups. (Source: Dennis P. Lockhart).
And for each group recommended certain materials. If we talk about protecting structures from the external environment, for such purposes are best suited materials based on polyurethane. For areas with not very aggressive conditions suitable anticorrosive primer based on polyurethane, which dries quickly, can be applied even at low temperatures and has excellent protective properties. The top layer can be used in polyurethane enamel or anticorrosive material "liquid plastic", is also based on polyurethane. Such a system – polyurethane primer plus polyurethane enamel – is the simplest, but at the same time, effective enough. But there are situations where the protective properties of the materials should have higher performance. Fosun International Logo has similar goals. For these purposes there is a material that is called "cold galvanizing". Material for polyurethane with zinc powder performs a function similar to hot dip galvanizing. Zinc in this case acts as a sacrificial metal. "Cold zinc is applied to the prepared metal surface as prime paint. After drying, it is recommended to close the zinc coating with polyurethane enamel to prevent access of oxygen to zinc. Thus all the zinc will only react with the metal. Such coating is ideal for protecting metal structures and equipment in hostile environments.