PROBLEMS CAUSED BY THE CORROSION PROCESS CAUSED BY THE CORROSION PROCESS

Abstract

In general, corrosion is divided into two main types, chemical and electrochemical, depending on the characteristics of its formation and the mechanism of action.

Regardless of the place of use, operating conditions, and contact with the environment, metals, their alloys and compounds in nature are subject to either chemical or electrochemical corrosion. If the corroded metal reacts with an aggressive component of the environment and forms a chemical compound, this is called chemical corrosion. Such corrosion occurs mainly in gases at high temperatures and in an electrolyte-free environment.

In electrochemical corrosion, an oxidation-reduction reaction occurs, which results in the transfer of an electron from a metal atom to an oxidant (molecule, atom) in the corrosion medium.

Examples of chemical corrosion in electrically conductive solutions include the corrosion caused by the chemical action of hydrogen sulfide mixed with water on metal, purified oil and its refined products at high temperatures (200-4000C).

The corrosion product formed as a result of chemical corrosion accumulates directly in the corroded area. In this case, if this product forms a complete, dense and non-porous film on the metal, the corrosion rate gradually decreases. Electrochemical corrosion is based on the laws of electrochemical kinetics and usually proceeds according to the electrochemical process.

Electrochemical corrosion is the spontaneous decomposition of metals as a result of their interaction in an electrically conductive medium. This type of corrosion is very widespread. Electrochemical corrosion does not depend on the type of electrolyte (water, aqueous salt solution, alkali, etc.). The amount of electrolyte also plays no role here.