About Corrosion

CORROSION COSTS

Corrosion is a process of unintentional destruction of construction materials caused by physical, chemical and biological agents. It is a spontaneous process that causes enormous damage to the economy. It has been found that annual costs of corrosion of metals, including corrosion protection measures in highly industrialized countries, account for about 3 % of their national income. This percentage does not cover the costs of secondary damage caused by corrosion, eg. accidents, human health hazards, production losses, heavy ecological catastrophes, deterioration of the monumental heritage etc. The above indicates the great importance of timely and high-quality corrosion protection.

CORROSION FORMS

Since the corrosion is a very wide term, there are several different corrosion classifications:

According to the mechanism: chemical and electrochemical

According to the appearance of a corrosion attack: uniform (general) corrosion and localized corrosion (eg. galvanic, pitting, intercrystalline, etc.)

According to the corrosive media: atmospheric corrosion, corrosion in the soil, corrosion in electrolytes and nonelectrolytes

Special forms of corrosion: corrosion due to stray current, crevice corrosion, stress corrosion, corrosion fatigue, erosion corrosion, microbiologically influenced corrosion etc.

CORROSION PROTECTION

Research has shown that one-fourth of the damage caused by corrosion can be prevented by the use of modern technologies. Metal can be protected from corrosion by various methods.

The most common methods for corrosion protection of metals are:

Electrochemical protection (cathodic and anodic)

Protection by Corrosion Treatment (by removing corrosion activators and by introducing corrosion inhibitors into the aggressive environment)

Coatings (metal and non-metallic coatings and inorganic and organic coatings).