TY - JOUR
T1 - Corrosion behaviour and galvanic coupling with steel of Al-based coating alternatives to electroplated cadmium
AU - Fasuba, O. A.
AU - Yerokhin, A.
AU - Matthews, A.
AU - Leyland, A.
PY - 2013/8/15
Y1 - 2013/8/15
N2 - The galvanic corrosion behaviour of bare steel coupled to steel with an Al-Zn flake inorganic spin coating, an Al-based slurry sprayed coating, an arc sprayed Al coating and electroplated cadmium has been investigated. The sacrificial and galvanic behaviour of the coatings was studied in 3.5 wt. % NaCl solution using open-circuit potential, potentiodynamic polarisation and electrochemical noise measurements. The coatings were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Experimental results showed that the Al-based slurry sprayed coating exhibited an open-circuit potential closer to the steel substrate than other coatings, as well as a low corrosion current density and a more positive corrosion potential. In terms of the galvanic suitability of the investigated coatings for the steel substrate, both the Al-Zn flake inorganic spin coating and the Al-based slurry sprayed coating show low galvanic current, in comparison with the arc sprayed Al coating and electroplated cadmium. This behaviour confirms their superior cathodic protection capability and galvanic compatibility over other coatings tested. Electrochemical noise measurements provide accurate information on the coatings' galvanic behaviour, which can be complimented by the data obtained from superposition of potentiodynamic corrosion scans of the coating and bare steel, provided that the corrosion potential difference between the two materials does not exceed 300 mV
AB - The galvanic corrosion behaviour of bare steel coupled to steel with an Al-Zn flake inorganic spin coating, an Al-based slurry sprayed coating, an arc sprayed Al coating and electroplated cadmium has been investigated. The sacrificial and galvanic behaviour of the coatings was studied in 3.5 wt. % NaCl solution using open-circuit potential, potentiodynamic polarisation and electrochemical noise measurements. The coatings were characterised by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction. Experimental results showed that the Al-based slurry sprayed coating exhibited an open-circuit potential closer to the steel substrate than other coatings, as well as a low corrosion current density and a more positive corrosion potential. In terms of the galvanic suitability of the investigated coatings for the steel substrate, both the Al-Zn flake inorganic spin coating and the Al-based slurry sprayed coating show low galvanic current, in comparison with the arc sprayed Al coating and electroplated cadmium. This behaviour confirms their superior cathodic protection capability and galvanic compatibility over other coatings tested. Electrochemical noise measurements provide accurate information on the coatings' galvanic behaviour, which can be complimented by the data obtained from superposition of potentiodynamic corrosion scans of the coating and bare steel, provided that the corrosion potential difference between the two materials does not exceed 300 mV
KW - Coatings
KW - Corrosion
KW - Electrochemical techniques
KW - Electron microscopy (SEM)
UR - http://www.scopus.com/inward/record.url?scp=84879910912&partnerID=8YFLogxK
U2 - 10.1016/j.matchemphys.2013.04.035
DO - 10.1016/j.matchemphys.2013.04.035
M3 - Article
AN - SCOPUS:84879910912
SN - 0254-0584
VL - 141
SP - 128
EP - 137
JO - Materials Chemistry and Physics
JF - Materials Chemistry and Physics
IS - 1
ER -