Generation of hydroxyl radicals by sonochemistry: Effects on the electrochemical behaviour of a 316L stainless steel

In this study, water radiolysis occurring in nuclear power plants was simulated by sonochemistry. Generated hydroxyl radicals can recombine in others species such as H2O2 and H2. It is shown that solution conductivity is an important parameter on the evolution of open circuit potential due to the thickness variation of the diffusion layer which may contain sonolysed species (OH, H2, H2O2) in different concentrations. Dissolved gases have also an impact on the 316L electrochemical behaviour. Increase of gas solubility leads to cavitation activity enhancement and further hydroxyl radical production. The latter leads to increased current density values under irradiation.

Research highlights
► Presence of water sonolysis products (OH, H2O2 and H2) in diffusion layer affect electrochemical behaviour of SS.
► OCP jump is more abrupt with thinner diffusion layer.
► Current densities increase under ultrasonic irradiation.
► Cavitation activity grows with gas solubility and leads to an increase of sonolysis products.
► Growth of concentration of sonolysis products yields to an increase of current densities values.