Electrochemical studies on the corrosion resistance of Zn–Ni–Co coating from acid chloride bath

• Published in: Applied physics. A, Materials science & processing Vol. 126; no. 10
• Main Authors: Bhat, Ramesh S., Manjunatha, K. B., Prasanna Shankara, R., Venkatakrishna, K., Hegde, A. Chitharanjan
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.10.2020; Springer Nature B.V
• Subjects: Applied physics; Atomic force microscopes; Atomic force microscopy; Cathodic coating (process); Characterization and Evaluation of Materials; Chemical composition; Cobalt; Condensed Matter Physics; Corrosion effects; Corrosion prevention; Corrosion resistance; Corrosion resistant steels; Corrosion tests; Cost analysis; Current density; Current efficiency; Electrochemical analysis; Electrode polarization; Gelatin; Industrial applications; Machine tools; Machines; Manufacturing; Materials science; Nanotechnology; Nickel; Optical and Electronic Materials; Optimization; Photoelectrons; Physics; Physics and Astronomy; Processes; Protective coatings; Steel structures; Surfaces and Interfaces; Thin Films; X ray analysis; Corrosion resistance; Ternary alloy; Cyclic polarization; Electroplating; Tafel plot
• ISSN: 0947-8396; 1432-0630
• DOI: 10.1007/s00339-020-03958-9

Anticorrosive deposits are a valuable approach to defending against corrosion from mild steel structures/machinery equipment. The Zn–Ni–Co coating has been deposited on low carbon steel surfaces using environment friendly optimized acidic chloride bath with ZnCl 2 ·6H 2 O, NiCl 2 ·6H 2 O, CoCl 2 ·6H 2 O, sulphanilic acid (C 6 H 7 NO 3 S) and gelatin (C 6 H 8 O 6 ). The standard Hull cell technique has been adopted for the optimization of bath components and experimental conditions, for the superior corrosion resistant coating. The corrosion test with potentiodynamic polarization method was performed to investigate the role of pH on the film quality and corrosion performances of the films. Further, the effect of current densities on corrosion resistance, thickness and hardness, have been investigated. Cyclic voltammetry technique has been used to test the electrochemical properties of the Zn–Ni–Co coating in acidic solutions. The results revealed that the increase in the current density favoured the increase in Ni and Co content in the deposit, showed higher corrosion resistance and higher cathodic current efficiency. The structural and morphological characteristics of the alloy coating have been obtained through scanning electron microscopy and X-ray diffraction techniques. The atomic force microscope was used to examine the topographic structure of the coating. X-ray Photoelectron spectroscopy was used to determine the chemical composition of alloy coatings and verified by energy dispersive X-ray analysis. The results indicate that a new and low-cost chloride bath for Zn–Ni–Co coating exhibit superior corrosion resistance properties and can be implement in various industrial applications such as automobiles, machine tools etc.