Cathodic processes in intergranular corrosion of nickel-chrome stainless steel
Abstract
Cathodic processes in intergranular corrosion of nickel-chrome stainless steel
Incoming article date: 20.02.2019The nature of cathodic reactions occurring during intergranular corrosion (ICC) on stainless steel 08X18H10T in a solution of 0.5 M H2SO4 + 0.01 M KCNS is considered. Evaluation of the thermodynamic potential of various reactions with components of the solution showed that the ICC process in this system proceeds with mixed oxygen-hydrogen depolarization. When the temperature rises, an intensification of the cathode process occurs, which is associated with a decrease in the overvoltage of the reduction of oxidants. Forced medium movement at low temperatures also facilitates the cathodic process, and at elevated temperatures the effect of convective medium movement decreases. This is due to the decrease in the proportion of oxygen involved in the cathode process, since its concentration in solution increases with increasing temperature.
Keywords: intergranular corrosion, stainless steel, temperature and hydrodynamic conditions