Effect of cupric sulfate on the microstructure and corrosion behavior of nickel-copper nanostructure coatings synthesized by pulsed electrodeposition technique

• Published in: Corrosion science Vol. 147; pp. 246 - 259
• Main Authors: Do, Quangquan, An, Hongze, Wang, Guoxing, Meng, Guozhe, Wang, Yangqiu, Liu, Bin, Wang, Junyi, Wang, Fuhui
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.02.2019; Elsevier BV
• Subjects: Coated electrodes; Coating; Copper; Copper sulfate; Corrosion; Corrosion effects; Corrosion resistance; Electrochemical impedance spectroscopy; Electrodeposition; Microscopy; Microstructure; Morphology; Nickel; Passive film; Polarization; Protective coatings; Scanning electron microscopy; Synthesis; Transmission electron microscopy; Polarization; Electrodeposition; Passive film; Coating; Corrosion
• ISSN: 0010-938X; 1879-0496
• DOI: 10.1016/j.corsci.2018.11.017

M–S plots of Ni-Cu nano alloy coatings synthesized from bath with (a) 0, (b) 2.5, (c) 5 and (d) 7.5 g/L cupric sulfate in 0.3 M NaCl solution after 30 min passivation at 75, 100, 125, 150, 175 and 200 mVSHE. [Display omitted] •Passive films formed on Ni-Cu coatings showed the n-type in NaCl solution.•Cu in Ni-Cu coatings can markedly retard the reactions at the interface.•Cu+ dopants to nickel oxide can enhance corrosion resistance of Ni-Cu coatings. In this work, Ni-Cu nano-alloying coatings were synthesized by pulsed electrodeposition technique from electrolyte with 0, 2.5, 5 and 7.5 g/L cupric sulfate. The effect of cupric sulfate on the microstructure, micro-morphology, and corrosion behavior of samples were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). A Varying amount of Cu was found to co-deposit in the coatings. The adequate amount of Cu can markedly enhanced the corrosion resistance of the coating due to the enhanced resistance to reactions at the metal|passive film (m|f) interface and reduction of oxygen vacancies by the dopant of Cu+ in the passive film.