Electrodeposition study of the Cu-Zn-Mo system in citrate/sulfate medium

Hugo Sousa Santos,Murilo Fernando Gromboni,Lucia Helena Mascaro,Alessandra Alves Correa

doi:10.26850/1678-4618eqj.v44.1si.2019.p26-35

Hugo Sousa Santos, Murilo Fernando Gromboni + Show 2 more

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https://doi.org/10.26850/1678-4618eqj.v44.1si.2019.p26-35

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Abstract

Alloys and composites that contain molybdenum have been studied due to their excellent properties, such as corrosion resistance and catalytic activity. In this work, the parameters for Cu-Zn-Mo system electrodeposition were studied, such as deposition potentials and concentration of electroactive species. The deposition potentials were examined using cyclic voltammetry and anodic linear stripping voltammetry (ALSV), the deposit morphology was evaluated using scanning electron microscopy (SEM) and crystallographic characterization was carried out for X-ray diffraction (XRD). The voltammetry studies indicated co-deposition of the metals in potentials more negative than -1.2 V, and a potential deposition at -1.5 V was chosen. The coatings presented morphology compact with small agglomerated particles with cauliflower structures, and the content of molybdenum, copper, and zinc ranged from 5 to 8%, 30 to 40% and 20 to 28%, respectively.

Highlights

Alloys and composites of zinc (Zn) and copper (Cu) commonly called brass have excellent properties such as mechanical strength, malleability and resistance against corrosion; in addition, they are considered to be weakly harmful to the environment[1,2]
This current is due to the evolution of H2, which is facilitated by the higher amount of Mo oxides/hydroxides deposited that is a catalytic species for hydrogen evolution reaction (HER)[33]
An increase of MoO42- concentration in the baths facilitates the deposition of molybdenum species; it leads to a higher evolution of hydrogen, which can lead to lower deposition efficiency and poor structure of the coatings

Summary

Introduction

Alloys and composites of zinc (Zn) and copper (Cu) commonly called brass have excellent properties such as mechanical strength, malleability and resistance against corrosion; in addition, they are considered to be weakly harmful to the environment[1,2]. An alloy/composite composed of Cu, Zn and Mo may have applicability as corrosion resistant coating and electrocatalytic material. Methods that use thermal energy, such as thermal spraying[11] and melting metal in a vacuum or inert atmosphere[12], are utilized to get these materials, but both methods are costly and expend a great deal of energy[13]. A reasonable option is electroplating because it is a generally simple technique, inexpensive and broadly utilized in the production of composites, metallic coatings, alloys and semiconductors on different substrates[14,15]. Recent research shows the possibility of Mo deposition with Zn and Cu14,16-18. In these studies, the Zn-Mo composite is proposed as a corrosion resistant coating with low danger and environmentally friendly, in contrast to other anticorrosive alloys containing cadmium and chromium. Kazimierczak et al, in another study, Eclética Química Journal, vol 44, special issue, 2019, 26-35

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