The Effect of Direct and Pulsed Current in the Presence of Surfactants on the Electrodeposition of Zn–SiC Nanocomposite Coatings

Honorata Kazimierczak,Noam Eliaz,Krzysztof Szymkiewicz,Eliezer Gileadi

doi:10.3390/coatings9020093

Abstract

Zn–SiC nanocomposite coatings were electrodeposited from aqueous citrate electrolytes using either direct current deposition (DCD) or pulsed electrodeposition (PED). The effects of various surface-active organic compounds (SDS, gum arabic, gelatin, CTAB, PEG 20000, and Triton X–100) on the coatings’ surface morphology and chemical composition were studied. The influence of pulse frequency and duty cycle on the percentage of the SiC nanoparticles (NPs) incorporated and on the quality of the deposits was also investigated. The amount of SiC NPs incorporated in the Zn matrix was similar for layers obtained by DCD compared to PED. The Zn–SiC coating deposited by PED exhibited a more fine-grained surface morphology. The percentage of SiC co-deposited with Zn was mainly affected by the type of surfactant used. The ionic surfactants (cationic gelatin and CTAB or anionic gum arabic) allowed the co-deposition of considerably higher amounts of SiC NPs with Zn, compared to the non-ionic compounds PEG 20000 and Triton X–100. However, the use of high molecular weight organic compounds such as gelatin and gum arabic led to aggregation of SiC NPs within the Zn matrix.

Highlights

Zinc is a vital metal from technological and industrial perspectives, due to its key role as a component of protective coatings
Citrates provide the stabilization of the pH. Of electrolyte solutions, they are widely used in provide the stabilization of the pH of electrolyte solutions, they are widely used in thethe electrodeposition of zinc its alloys
The only variable in the bath chemistry was the type of organic additive

Summary

Introduction

Zinc is a vital metal from technological and industrial perspectives, due to its key role as a component of protective coatings. The incorporation of ceramic particles into the zinc matrix can be considered as an effective way to improve its mechanical and corrosion properties. The incorporation of second phase micro- or nano-particles (NPs) into a metal matrix may result in the substantial improvement of a variety of properties of the composite material (such as microhardness, yield strength, tensile strength, wear and corrosion resistance, self-lubrication, high-temperature inertness, and chemical and biological compatibility) in comparison with the characteristics of a pure metal or alloy, it remains the subject of much research [1,2,3,4]. Electrodeposition offers a versatile way to produce high-quality composite coatings with well-dispersed NPs, a smooth surface, and a good coating/substrate bonding, in a single step, at low cost, and using an controllable and reproducible procedure. It can ensure continuous processing and the capability to handle complex geometries or non-line-of-sight surfaces [1,5,6].

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