Protection of low-carbon steel in hydrochloric acid solution with mixtures of inhibitors containing surfactants

The corrosion of low-carbon steel in 2 M HCl was studied in the temperature range t = 25-95°C. For this environment, the possibility of creating mixed corrosion inhibitors (CIs) containing surfactants – catamin AB and cocamidopropylbetaine (CAPB) – has been considered. It has been shown that the compositions catamin AB + urotropine and CAPB + urotropine are promising for the creation of effective CIs steel in 2 M HCl. The optimal total content of mixtures of CIs in an aggressive environment is 5 mM. The molar ratio of surfactant and urotropine in mixtures of CIs is 1:9. The composition of 0,5 mM CAPB + 4,5 mM urotropine effectively slows down the corrosion of 08PS steel in 2 M HCl at t ≤60°C, ensuring a steel corrosion rate of no higher than 3.9 g/(m 2 ×h). At t = 60°C, steel corrosion slows down by 27 times. The composition of 0,5 mM catamin AB + 4,5 mM urotropine inhibits steel corrosion more strongly. A significant decrease in the corrosion rate of steel in its presence is observed at t ≤80°C, when it does not exceed 6.9 g/(m 2 ×h). The corrosion process at t = 80°C is slowed down 90 times. It is noted that replacing single-component CIs with two-component mixtures makes it possible to increase the efficiency of steel protection and reduce the consumption of the most expensive components used for their production.