EFFECT OF ACETIC ACID ON THE RESISTANCE TO LOCAL CORROSION OF 13% CHROMIUM STEEL IN CO2-CONTAINING ENVIRONMENTS

The effect of concentration of acetic acid ranged from 0 to 5000 ppm on the processes of initiation and propagation of pitting corrosion in martensitic class stainless steel containing 13% chromium was studied. The research was conducted in CO2-saturated 5 wt. % sodium chloride solutions at various temperatures using electrochemical methods, including cyclic potentiodynamic polarization and pulse potentiostatic technique. The results show that the presence of acetic acid stimulates the formation and development of localized corrosion, increases the metal dissolution rate within the pits, promotes the initiation of a greater number of pits, and facilitates their spread on surface, leading to the expansion due to smaller pits adjacent to the main ones.