PROTECTION FROM CORROSION BY ORGANIC COATING
The corrosion is a phenomenon which is widely observed with almost all metals. The most common and convenient method of protecting a metal against corrosion is by a coating, especially an organic coating. The main function of an organic coating is to serve as a protective barrier against corrosion besides having an aesthetic appeal.
Organic coating are inert organic barriers like paint varnishes, lacquers and enamels. Plied on metallic surfaces and other constructional materials for both corrosion protection and decoration.
The protection value of such coating depends on:
1. Its chemical inertness to the corrosive environment
2. Its good surface addition.
3. Its impermeability to water, salts and gases
4. Its proper application method.
Paint is a mechanical dispersion mixture of one or more pigments in a vehicle, the vehicle is a liquid consisting of non volatile film forming material drawing oil and highly volatile solvent, thinner .When a paint is applied to a metal surface usually by brushing or spraying, the thinner evaporates while the drawing of oil slowly oxidized forming a dry pigmented film.
Paint is used to protect, preserve and decorate (such as adding color), or add functionality to an object or surface by covering it with a pigmented coating. An example of protection is to retard corrosion of metal. An example of decoration is to add festive trim to a room's interior. An example of added functionality is to modify light reflection or heat radiation of a surface. Another example of functionality is the use of color to identify hazards or to identify the function of equipment, such as pipelines or military ammunition.
Paint can be applied to almost any kind of object. It is used, among many other uses, in the production of art, in industrial coating, as a driving aid (road surface marking), or as a barrier to prevent corrosion or water damage. Paint...