The Roles of Fluid Hydrodynamics, Mass Transfer, Rust Layer and Macro-Cell Current on Flow Accelerated Corrosion of Carbon Steel in Oxygen Containing Electrolyte

Abstract

The flow accelerated corrosion (FAC) of EH 36 carbon steel in the oxygen containing flowing electrolyte is studied using multi-electrode array arranged in a jet rig system. The FAC of the working electrodes (WEs) under both uncoupled and coupled conditions are investigated in conjunction with computational fluid dynamics (CFD) simulation. Results show that a higher mass transfer rate would lead to a higher FAC rate when the WEs are uncoupled. The rust layer could retard the oxygen diffusion, resulting in the FAC rate decreasing. The mass transfer process and the distribution of the rust layer are significantly influenced by the fluid hydrodynamics. However, when the WEs are coupled together, serious FAC damage would occur on the WEs where lower mass transfer rates are registered. The macro-cell currents would become the main lead of FAC propagation at coupled conditions.

Imaging and Quantifying the Chemical Communication between Single Particles in Metal Alloys

“…It is also important to note that the transition between different dissolution/precipitation kinetic regimes in numerical simulations (Figure ) was defined using an empirical parameter related to the inhibition of cathodic sites, which is also connected to the activities of individual particles. Existing literature suggests that factors such as thickness, composition, and structure of dynamically evolving surface films can influence the kinetics of cathodic reactions. − In light of this, direct in situ measurements of local electrochemical activity are necessary to complement the in situ observation of surface deposition/dissolution and to rigorously develop a physical model for chemical communication. An intriguing direction for future research would be to investigate the use of local complementary probing techniques, such as nanopipet methods in a combined optoelectrochemical approach, − to supplement optical observations with direct local electrochemical measurements.…”

Imaging and quantifying the chemical communication between single particles in metal alloy

“…It is worth pointing out that the transition between the different regimes of dissolution/precipitation kinetics in numerical simulations was defined with an empirical parameter of the inhibition of the cathodic sites. While the exact physical meaning of this parameter is unknown, some literature suggests that the thickness, composition, and structure of dynamically evolving surface films can have an impact on the kinetics of cathodic reactions [46][47][48]. In this vein, a direct in-situ measurement of local electrochemical activity is required to complement the in-situ observation of the surface deposition/dissolution and rigorously elaborate on the physical model of the chemical communication.…”

Flow accelerated corrosion and erosion−corrosion behavior of marine carbon steel in natural seawater

“…Since the electrolyte is almost stagnant beneath the rust layer, the oxygen diffusion from the bulk solution to the steel interface is retarded. The oxygen concentration difference between the rust-covered area and the bare steel area could facilitate the pitting initiation beneath the rust layer 6 . Meanwhile, it is difficult for the generated cations to diffuse from the rust-covered area to the bulk solution (Fig.…”

“…Seawater is always in motion due to the effects of tidal attraction, ocean current, and wind power. The contact between steel structures and moving seawater might induce flow accelerated corrosion (FAC) and erosion−corrosion [6][7][8][9] . Such issues are more obvious in high-speed vessels and underwater vehicles, where cruising speeds could reach above 10 m s −110- 12 .…”