abstract
Featured Application The black coatings described in this work find application in decorative finishes, optical instruments, and photovoltaic modules. This work compares different electrodeposition procedures to produce nickel black coatings as greener and less toxic alternatives to Cr(VI)-based coatings used in different applications. Nickel and nickel-plated brass served as substrates in studies with a Hull cell and polarization curves. After a set of comparative experiments, the best electrodeposition procedure was further studied and optimized. Optimal conditions were found with a bath consisting of 75 g/L NiCl2 center dot 6H(2)O + 30 g/L NaCl and a current density of 0.143 A dm(-2) applied for 5 min at room temperature. Furthermore, a pre-treatment with 18.5 vol.% of hydrochloric acid in water was found to be necessary to warrant good coating adhesion to the substrate. The black color is attributed to the development of a nanostructured surface that absorbs the incident light. Corrosion testing was performed in 0.5 M NaCl aqueous solution using electrochemical impedance spectroscopy (EIS) and polarization tests.
keywords
SOLAR-ABSORBER COATINGS; CHROMIUM; ZINC
subject category
Chemistry, Multidisciplinary; Engineering, Multidisciplinary; Materials Science, Multidisciplinary; Physics, Applied
authors
Mennucci, MM; Montes, R; Bastos, AC; Monteiro, A; Oliveira, P; Tedim, J; Ferreira, MGS
our authors
António Alexandre Cunha Bastos
Assistant Researcher
João Tedim
Associate Professor
Marina Martins Mennucci
Post-Doc Fellowship
Mário Guerreiro Silva Ferreira
Retired Professoracknowledgements
This research was funded by project ON-SURF-Mobilizar Competencias Tecnologicas em Engenharia de Superficies, Projeto no POCI-01-0247-FEDER-024521.