Corrosion is translated from Latin as "corrosion". This is the name of the process of destruction of any material (wood, ceramics, polymer, metal) as a result of exposure to the environment, whether it be soil, air, water (sea, river, marsh, lake, underground) or any other environment. In relation to metals, the term corrosion of metals is replaced by the generalized word "rust". For example, during oxygen corrosion of iron in water, hydrated iron hydroxide is formed - ordinary rust.
Corrosion of metals leads to great losses - for Russia, this is the annual loss of millions of tons of valuable metals. More than 10% of the annual production of metal pipes becomes unusable due to corrosion. For the same reason, metal structures of various structures buried in the ground, tanks for storing oil and other minerals become unusable in 3-4 years if they are not protected from the destructive effect of soil-soil corrosion. Electrical and communication cables, bottoms of boats, car hulls and other facilities are subject to corrosion.movement.
Soil-soil corrosion of metals is an electrochemical process that depends on factors such as the chemical composition of soils, their moisture and air permeability, the type of metal, its uniformity, and the nature of the surface of metal objects.
In order to save metal in the ground (water, air, other environments), you need to know the reasons that can cause corrosion of metals. To obtain data on the degree of soil corrosion activity necessary for the development of measures to protect metal structures from corrosion, comprehensive field and laboratory studies of soils are carried out.
Protection of metals from corrosion is based on the following methods:
1. increase in chemical resistance for structural materials (introduction of corrosion-resistant elements into alloys or, conversely, elimination of corrosion-accelerating impurities from the alloy);
2. isolation of the metal surface from the impact of an aggressive environment (application of paints and varnishes on metal, insulating films, galvanic coatings);
3. electrochemical protection - under the influence of a superimposed external current on a metal structure;
4. reducing the aggressiveness of the environment by introducing corrosion inhibitors (arsenates, chromates, nitrites), deoxygenation or neutralization of the environment.
These methods are divided into 2 groups. The first two methods are performed before the operation of a metal product at the stage of its design or manufacture, andit will be impossible to change something during the operation. The other two methods are carried out only when the metal product is in operation, and it is possible to change the protection mode depending on the changed actual environmental conditions.
Such a question as the protection of metal from corrosion remains relevant at the present time, requiring an integrated approach to the search for modern design solutions, improvement of old proven protective methods and means.
