On appearance corrosion is distinguished: spots, ulcers, points, intracrystalline, subsurface. On character of the corrosion environment distinguish the following main types of corrosion: gas, atmospheric, liquid and soil.
For sheet and film polymeric materials it is necessary to know the size of their adhesion with the protected surface. A number of the nonmetallic chemically resistant materials which are widely used in anticorrosive equipment contains aggressive connections which at direct contact with a surface of metal or concrete can cause formation of by-products of corrosion in the structure that, in turn, will reduce the size of their adhesion with the protected surface. These features need to be considered when using this or that material for creation of a reliable anticorrosive covering.
Corrosion: process of destruction of materials owing to chemical or electrochemical processes. An erosion – mechanical destruction of a surface. On nature of the process corrosion is divided into two main groups: chemical and electrochemical. Chemical corrosion proceeds in nonelectrolytes – the liquids which are not carrying out electric current and in dry gases at high temperature. Electrochemical corrosion happens in electrolytes and in damp gases and is characterized by presence of two in parallel the going processes: oxidizing (dissolution threw also recovery (release of metal from solution.
Atmospheric corrosion belongs to the most widespread type of electrochemical corrosion as the majority of metal designs are operated in atmospheric conditions. The corrosion proceeding in the conditions of any damp gas can be also referred to atmospheric corrosion.