Co-Ni alloy coatings electrodeposited using real leachates generated from positive electrodes of Ni Cd batteries

Autor: Román Cabrera-Sierra, Rosa Luna-Sánchez, Fabiola S. Sosa-Rodríguez, Liliana Altamirano-Garcia, Jorge Vazquez-Arenas
Rok vydání: 2021
Předmět:
Zdroj: Surface and Coatings Technology. 425:127672
ISSN: 0257-8972
DOI: 10.1016/j.surfcoat.2021.127672
Popis: The feasibility to recover a Co Ni alloy is evaluated in the present study by electrodeposition using real liquors from the leaching of Ni Cd batteries (positive electrodes) in H2SO4, with saccharin as additive. Ni content in the alloy rises with increasing the applied current density for all baths, while current efficiencies higher than 70% are achieved with the use of the sulfate-chloride electrolyte containing saccharin. The additive could strongly interact with chloride to suppress the occurrence of parasitic reactions (H+ and H2O reductions), while the formation of chlorocomplexes particularly of Ni(II) accelerate their reduction on the electrode surface. This mixed electrolyte also enables to obtain more pure Co Ni alloys at −600 A m−2, as detected in the analysis of O composition (5.12 at.%/1.36 wt%). The impurities favorably affected the contributions of both parasitic reactions. Saccharin predominantly blocks H2O reduction at high overpotential, but not H+ discharge at low overpotential. The particle size and shape of the alloys strongly rely on current density imposed and bath composition. All deposits contain Cd, although its content is considerably less favored as the current density is increased to −600 A m−2. XRD confirms the microstructure of the formed alloys, mainly comprised of the following planes: Ni(111) and Co(111), CoOOH(003) and Cd(OH)2(001).
Databáze: OpenAIRE
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