The affinity of some metals in a corrosive environment initially increases normally with increasing concentration of corrosive agents (oxidizing power of the solution), and metal corrosion is intensified, but at a certain concentration of corrosive agents, the corrosion rate suddenly decreases significantly and the metal loses its affinity and becomes inactive. The reason for the reduction in corrosion at a certain concentration of oxidizing components is the formation of a protective or inactive layer on the metal surface. The protective layer can be oxide, hydroxide or other compounds. This phenomenon is called rusting.

Chemically, the alkalinity of water indicates its capacity to be neutralized by an acid. Neutralization of water means that the pH of the water reaches about 4.5. The alkalinity of natural waters is due to the presence of hydroxides, carbonates, and bicarbonates.

Boiler systems encounter two gases, oxygen and carbon dioxide, dissolved in the water entering them during their working process. The presence of these gases causes corrosion in boilers and heating systems and will disable the device in the long term. Usually, dissolved oxygen in water is removed in two ways, physically and chemically.

The factor affecting the corrosion and sedimentation of water is alkalinity. For example, the alkalinity of water used in steam boilers must be high enough to prevent corrosion of the boiler walls.