Protecting metals against corrosion

Corrosion is the destruction of a metal or alloy as a result of its oxidation under the influence of the environment. Car body parts are the most susceptible to corrosion. Corrosion not only weakens the metal, it can also cause the bodywork to fail.

If we take the most common type of corrosion of an iron-based alloy in an air environment, it can be represented as follows: iron (Fe) is oxidized to FeO or Fe2O3 under the influence of oxygen (O2) of air, and under the influence of moisture contained in the air, rust is formed on the metal surface. In addition, there are electrochemical processes of oxidation of iron and its transformation into rust, which over time affects deeper and deeper layers of the metal.

Without going into detail, corrosion protection methods can be divided into passive and active.

Passive are also called barrier, i.e. isolating the metal surface from the interaction with the environment. This coating of surfaces with varnishes, paints, enamels, etc. Many advantages, but the main disadvantage - short-lived.

Active methods are mainly by applying a layer of protective metal to the metal to be protected. If you use a metal that is more active than the metal to be protected, you get an anodic coating. These coatings include chrome plating and galvanizing. If you use a less active metal, you get the cathodic coating. These are tinning and nickel plating.

Well, the methods of coating can be different: hot, cold and galvanic, by dipping, rubbing or spraying.

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