Sodium Nitrate As a Corrosion Inhibitor of Carbon Steel in Various Concentrations of Hydrochloric Acid Solution

In the chemical and petroleum industries, metals are used in over 90% of construction units. Iron and steel are widely used metals in the fabrication and manufacturing of petroleum field operating platforms. The exposures of metals to the effect of bases or acids in the various industries can be severe to the metals specifications and thus result in suddenly failure of materials in service. So that, the need to investigate the protection of metals when exposed to various environments, as this is a very important factor in the selection of material that determines the service life of it. In the present study, the effect of various concentrations ranging from (25 to 100 mg/l) of sodium nitrate was studied in inhibiting the corrosion of carbon steel placed in different concentrations of hydrochloric acid solution (1 M, 2 M, and 3 M), the results showed that the concentration of (75 mg/l) of sodium nitrate achieved the best inhibition of the acid used in all the concentrations used, as it reduced the corrosion rate by 48.91% for a concentration of 1 M, 39.38% for a concentration of 2 M, and 35.33% for a concentration of 3 M.