The influence of sodium nitrite concentration in inhibitor protection of structural elements working in aggressive environmental conditions

The durability of materials working in aggressive environments is mostly important in the design of structures and devices. Corrosion destruction is one of the main causes of material losses, reduced efficiency and safety of their use. Corrosion cannot be completely eliminated but it can be significantly reduced by using different methods of protection. Proper design of structures working in aggressive environments, the use of protective coatings or environmental modification significantly reduces the rate of corrosion. Corrosion inhibitors are also used to protect the structural elements. An addition of a small amount of a chemical compound or a mixture of corrosion inhibitor compounds results in a significant reduction of the corrosion rate. To select a proper corrosion inhibitor and proper concentration for a specific corrosion system, laboratory tests are carried out. The article presents the results of research on determining the effect of inhibitor - NaNO2 sodium nitrite - on the dissolution kinetics of model constructional steel in water environment and in an aqueous sodium chloride solution. The influence of inhibitor concentration in the range of 0.5-2.5 % on the corrosion rate of steel in a 5% solution of sodium chloride was estimated by assessing unit changes in mass and corrosion rates. The effectiveness of inhibitors was determined using the protection factor ν and the inhibitor efficiency Ef.