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Simulation of galvanic corrosion of magnesium coupled to a steel fastener in NaCl solution
Author(s) -
Jia J. X.,
Atrens A.,
Song G.,
Muster T. H.
Publication year - 2005
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/maco.200403855
Subject(s) - corrosion , materials science , galvanic cell , galvanic corrosion , kelvin probe force microscope , polarization (electrochemistry) , metallurgy , magnesium , cathodic protection , fastener , magnesium alloy , alloy , composite material , electrochemistry , chemistry , electrode , nanotechnology , atomic force microscopy
The galvanic corrosion of magnesium alloy AZ91D coupled to a steel fastener was studied using a boundary element method (BEM) model and experimental measurements. The BEM model used the measured polarization curves as boundary conditions. The experimental program involved measuring the total corrosion rate as a function of distance from the interface of the magnesium in the form of a sheet containing a mild steel circular insert (5 to 30 mm in diameter). The measured total corrosion rate was interpreted as due to galvanic corrosion plus self corrosion. For a typical case, the self corrosion was estimated typically to be ∼ 230 mm/y for an area surrounding the interface and to a distance of about 1 cm from the interface. Scanning Kelvin Probe Force Microscopy (SKPFM) revealed microgalvanic cells with potential differences of approximately 100 mV across the AZ91D surface. These microgalvanic cells may influence the relative contributions of galvanic and self corrosion to the total corrosion of AZ91D.