TY - JOUR
T1 - Corrosion behavior of composition modulated multilayer Zn-Co electrodeposits produced using a single-bath technique
AU - Thangaraj, V.
AU - Eliaz, N.
AU - Hegde, A. Chitharanjan
N1 - Funding Information:
Acknowledgment Thangaraj V. is grateful to NITK, Surathkal, for providing the Institute Fellowship that allowed carrying out this work.
PY - 2009/3
Y1 - 2009/3
N2 - Composition modulated alloy (CMA) electrodeposits of Zn-Co were produced from acid chloride baths by the single-bath technique. Their corrosion behavior was evaluated as a function of the switched cathode current densities and the number of layers. The process was optimized with respect to the highest corrosion resistance. Enhanced corrosion resistance was obtained when the outer layer was slightly richer with cobalt. At the optimum switched current densities 40/55 mA cm-2, a coating with 600 layers showed ~6 times higher corrosion resistance than monolithic Zn-Co electrodeposit having the same thickness. The CMA coating exhibited red rust only after 1,130 h in a salt-spray test. The increased corrosion resistance of the multilayer alloys was related to their inherent barrier properties, as revealed by Electrochemical Impedance Spectroscopy. The corrosion resistance was explained in terms of n-type semiconductor films at the interface as supported by Mott-Schottky plots.
AB - Composition modulated alloy (CMA) electrodeposits of Zn-Co were produced from acid chloride baths by the single-bath technique. Their corrosion behavior was evaluated as a function of the switched cathode current densities and the number of layers. The process was optimized with respect to the highest corrosion resistance. Enhanced corrosion resistance was obtained when the outer layer was slightly richer with cobalt. At the optimum switched current densities 40/55 mA cm-2, a coating with 600 layers showed ~6 times higher corrosion resistance than monolithic Zn-Co electrodeposit having the same thickness. The CMA coating exhibited red rust only after 1,130 h in a salt-spray test. The increased corrosion resistance of the multilayer alloys was related to their inherent barrier properties, as revealed by Electrochemical Impedance Spectroscopy. The corrosion resistance was explained in terms of n-type semiconductor films at the interface as supported by Mott-Schottky plots.
KW - Anomalous codeposition
KW - Composition modulated alloy (CMA)
KW - Corrosion resistance
KW - Electrodeposition
KW - Zn-Co coatings
UR - http://www.scopus.com/inward/record.url?scp=60349117527&partnerID=8YFLogxK
U2 - 10.1007/s10800-008-9677-1
DO - 10.1007/s10800-008-9677-1
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AN - SCOPUS:60349117527
SN - 0021-891X
VL - 39
SP - 339
EP - 345
JO - Journal of Applied Electrochemistry
JF - Journal of Applied Electrochemistry
IS - 3
ER -