Original scientific paper
https://doi.org/https://doi.org/10.5599/jese.2519
Alkaline etching of diffusion zinc coatings NiZn and CoZn as promising electrocatalysts for hydrogen evolution reaction
Natalya Amelina
; Chelyabinsk State University, 454001 Chelyabinsk, Russian Federation
Daria Zakharova
; Chelyabinsk State University, 454001 Chelyabinsk, Russian Federation
Alexander Biryukov
; Chelyabinsk State University, 454001 Chelyabinsk, Russian Federation
Dmitry Zakharyevich
; Chelyabinsk State University, 454001 Chelyabinsk, Russian Federation
Maxim Ulyanov
; Chelyabinsk State University, 454001 Chelyabinsk, Russian Federation
Abstract
Coatings based on NiZn and CoZn alloys were obtained by combining electrodeposition and diffusion galvanizing methods. The coatings are homogeneous and uniform, the zinc concentration is between 85.0 to 89.5 at.%, and consist of intermetallic phases of NiZn and CoZn, mainly γ-Ni2Zn11 and γ2-CoZn13. Alkaline etching of coatings is accompanied by selective dissolution of zinc, and the rate of dissolution of coatings increases with time. This dealloying is accompanied by a change in the morphology of the coatings - cracks, pits, and pores of considerable depth are formed. These defects contribute to the formation of galvanic coupling between the coating and the substrate, which leads to an increase in the dissolution rate. The electrochemical behavior of coatings after alkaline etching in the cathodic hydrogen evolution reaction was studied. The cathodic current of hydrogen evolution on coatings alkaline etching increases by 1.5 to 3 times compared to coatings before etching. This effect is greater on Ni-based coatings. Diffusion galvanizing followed by dealloying is a promising method for creating electrode materials for alkaline electrolysis with hydrogen evolution.
Keywords
Etched alloy coatings; dealloying; surface morphology; water electrolysis; cathodic polarization
Hrčak ID:
323687
URI
Publication date:
18.11.2024.
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