The cyclic multilayer alloy (CMA) coatings of Zn-Co have been developed galvanostatically on mild steel (MS), using single bath technique. Depositions were carried out using square current pulses. Corrosion behaviors of the coatings were evaluated by potentiodynamic polarization and electrochemical impedance method, supported by dielectric spectroscopy. The cyclic cathode current densities (CCCD’s) and number of layers were optimized for highest corrosion stability of the coatings. The CMA coating developed at 3.0/5.0 A/dm2, having 300 layers, represented as (Zn-Co) 3.0/5.0/300 was found to exhibit ~ 40 times better corrosion resistance compared to monolayer coating, developed from same bath for same time. Substantial improvement in the corrosion resistance of CMA coatings is attributed to layered coating, having alternatively different phase structures, evidenced by XRD study. The formation of multilayer and corrosion mechanism was analyzed using Scanning Electron Microscopy.
I. Ivanov and I. Kirilova, “Corrosion Resistance of Compositionally Modulated Multilayered Zn-Ni Alloys Deposited from Single Bath,” Journal of Applied Electrochemistry, Vol. 33, No. 3-4, 2003, pp. 239-244.
M. R. Kalantary, G. D. Wilcox and D. R. Gabe, “Production of Compositionally Modulated Alloys by Simulated High Speed Electrodeposition from a Single Solution,” Electrochimica Acta, Vol. 40, No. 11, 1995, pp. 1609- 1616. doi:10.1016/0013-4686(95)00085-S
I. Ivanov, T. Valkova and I. Kirilova, “Corrosion Resistance of Compositionally Modulated Zn-Ni Multilayers Electrodeposited from Dual Bath,” Journal of Applied Electrochemistry, Vol. 32, No. 1, 2002, pp. 85-89.
I. Kirilova, I. Ivanov and St. Rashkov, “Anodic Behaviour of Composition Modulated Zn-Co Multilayers Electrodeposited from Single and Dual Baths,” Journal of Applied Electrochemistry, Vol. 28, No. 6, 1998, pp. 1359- 1363. doi:10.1023/A:1003210404884
J. Y. Fei, G. Z. Liang, W. L. Xin and W. K. Wan, “Surface Modification with Zinc and Zn-Ni Alloy Compositionally Modulated Multilayer Coatings,” Journal of Iron and Steel Research, International, Vol. 13, No. 4, 2006, pp. 61-67. doi:10.1016/S1006-706X(06)60080-0
J. Yin Fei, G. Z. Liang, W. L. Xin and J. H. Liu, “Corrosion Performance of Zinc and Zinc-Cobalt Alloy Compositionally Modulated Multilayer (CMM) Coatings,” Jour- nal of Wuhan University of Technology, Materials Science Edition, Vol. 21, No. 4, 2006, pp. 40-44.
S. S. Chatha, H. S. Sidhu and B. S. Sidhu, “Characterisation and Corrosion Erosion Behaviour of Carbide Based Thermal Spray Coating,” Journal of Minerals and Materials Characterization and Engineering, Vol. 11, No. 6, 2012, pp. 569-586.
V. Thangaraj, N. Eliaz and A. Chitharanjan Hegde, “Corrosion Behavior of Composition Modulated Multilayer Zn-Co Electrodeposits Produced Using a Single-Bath Technique,” Journal of Applied Electrochemistry, Vol. 39, No. 3, 2009, pp. 339-345.
S. Samal, A. Bhattaacharyya and S. K Mitra, “Study on Corrosion behaviour of Pearlitic Rail Steel,” Journal of Minerals and Materials Characterisation and Engineering, Vol. 10, No. 7, 2011, pp. 573-581.
G. Trejo, R. Ortega, Y. Meas, E. Chainet and P. Ozil, “Effect of Benzylideneacetone on the Electrodeposition Mechanism of Zn-Co Alloy,” Journal of Applied Electrochemistry, Vol. 33, No. 5, 2003, pp. 373-379.
M. M. Younan, “Surface Microstructure and Corrosion Resistance of Electrodeposited Ternary Zn-Ni-Co Alloy,” Journal of Applied Electrochemistry, Vol. 30, No. 1, 2000, pp. 55-60. doi:10.1023/A:1003840519591
F. Elkhatabi, M. Sarret, and C. Muller, “Chemical and Phase Compositions of Zinc-Nickel Alloys Determined by Stripping Techniques,” Journal of Electroanalytical Chemistry, Vol. 404, No. 1, 1996, pp. 45-53.
G. Barcelo, E. Garcia, M. Sarret and C. Muèller, “Characterization of Zinc-Nickel Alloys Obtained from an Industrial Chloride Bath,” Journal of Applied Electrochemistry, Vol. 28, No. 10, 1998, pp. 1113-1120.
J. B. Bajat, M. D. Maksimovic, V. B. Miskovic-Stankovic, and S. Zec, “Electrodeposition and Characterization of Zn-Ni Alloys as Sublayers for Epoxy Coating Deposition,” Journal of Applied Electrochemistry, Vol. 31, No. 3, 2001, pp. 355-361. doi:10.1023/A:1017580019551
A. Petrauskas, L. Grinceviciene, A. Cesuniene and R. Juskenas, “Influence of Co2+ and Cu2+ on the Phase Composition of Zn-Ni Alloys,” Electrochimica Acta, Vol. 51, No. 27, 2006, pp. 6135-6139.
J. B. Bajat, V. B. Miskovic-Stankovic, “Protective Properties of Epoxy Coatings Electrodeposited on Steel Electrochemically Modified by Zn-Ni Alloys,” Progress in Organic Coatings, Vol. 49, No. 3, 2004, pp. 183-196.
P. Ganeshan, P. Swaminatha, Kumaraguru and B. N. Popov, “Development of Compositionally Modulated Zn-Ni Multilayer Deposits as Replacement for Cadmium,” Surface Coating and Technology, Vol. 201, No. 18, 2007, pp. 7896-7904.