Influence of Edge Effects on Local Corrosion Rate of Magnesium Alloy/Mild Steel Galvanic Couple

Abstract

The effect of the insulator-mixed-material edge on the galvanic corrosion rate of magnesium alloy (AE44)-mild steel (MS) couple is experimentally studied using scanning vibrating electrode technique (SVET), profilometry, and classical electrochemistry. The local and average corrosion rates estimated from the experimental depth of anodic attack profile of AE44-MS couple are validated by 2D and 3D corrosion numerical models. Our study demonstrates experimentally and theoretically that the presence of the insulator edge increases the local current density, which enhances the corrosion rate. The extent of the local corrosion rate enhancement and its effect on the overall corrosion rate of the mixed material is discussed and depends on the mixed material's geometry and the edge type.

Local Hydrogen Fluxes Correlated to Microstructural Features of a Corroding Sand Cast AM50 Magnesium Alloy

“…Finally, a mirror finish was produced using a 3 μm diamond paste (Dia3, Struers) with a Struers MD Dur cloth followed by a slurry of ethylene glycol and 0.04 μm colloidal silica (1:1 mixture) on a Struers MD Chem cloth for 2 min. 23 After aggregated silica was removed using sonication in anhydrous ethanol for 2 min, the sample was dried in an Ar stream.…”

“…Local scanning probe techniques such as several modes of scanning electrochemical microscopy (SECM), [13][14][15][16][17][18][19] scanning Kelvin probe force microscopy (SKPFM), [20][21][22] the scanning vibrating electrode technique (SVET) [23][24][25] and local electrochemical impedance spectroscopy (LEIS) 26 have been used to probe the heterogeneous surfaces of Mg alloys and to assess the electrochemical behavior of the different microstructural constituents responsible for microgalvanic corrosion. Among these techniques, SECM has the ability to quantify electrochemical fluxes in situ with high lateral resolution using a microelectrode (ME).…”

Facile Fabrication of a Superhydrophobic Surface with Robust Micro-/Nanoscale Hierarchical Structures on Titanium Substrate

“…The cracks on the surface are normally regarded as defects degrading anti-corrosion [ 30 ]. Undoubtedly, such uniform cracks would lead to the corresponding nanostructures by electrochemical etching (ECE) under the edge effect on the edges of those cracks [ 31 ].…”

Numerical Simulation of Galvanic Corrosion between Carbon Steel and Low Alloy Steel in a Bolted Joint

“…Simulation of galvanic corrosion between magnesium and aluminum has been performed by Lacroix et al [4], Deshpande [5][6][7], Jia et al [8], and Trinh et al [9] who have studied the corrosion of magnesium alloys in contact to mild steel under static conditions. The publications of Murer et al [10][11][12] and Shi and Kelly [13] in this context also gave an extended insight into the topic, especially in the very important choice of boundary conditions.…”