Effective particle dispersion via high-shear mixing of the electrolyte for electroplating a nickel-molybdenum disulphide composite

Abstract

The hydrophobic nature of molybdenum disulphide (MoS2) particles is a major challenge for electrodepositing uniform Ni-MoS2 composite coatings due to particle agglomerates present in the aqueous nickel plating bath. In this study, high-shear mixing was shown for the first time as a facile and effective way to achieve a narrow particle-size distribution and stable particle dispersions in the electrolyte, which were characterised by measuring particle-size distributions via dynamic light scattering. The influence of shear mixing duration and speed on particle dispersion in the electrolyte was investigated. The resulting Ni-MoS2 composite coating had a compact structure, showing a lower coefficient of friction and enhanced wear resistance in unlubricated wear tests. In comparison, magnetic stirring was less effective in breaking down particle agglomerates in the bath, which led to a porous and fragile deposit with poor tribological properties.

Electroplating of non-fluorinated superhydrophobic Ni/WC/WS2 composite coatings with high abrasive resistance

“…Since nanosized particles, such as WS2 and WC, are electrically conductive, the nickel ions can be reduced both on the nickel deposits and on the surface of nanoparticles. This growth mechanism has been investigated and described in the previous studies, such as Co/WS2 [30], Ni/WS2 [20,24], Ni/WC [29,31], Ni/P/WS2 [26] and Ni/MoS2 [25]. In this study, we found the surface morphology closely depended on the type and concentration of nanoparticles.…”

“…The WC NPs and WS2 NPs improved abrasive resistance of coatings; the combined effects are discussed below. The mechanism on one type of particle has been considered in our previous studies [20,25,26,28,29]. In addition, the current density of electrodeposition was fixed at 4 A dm -2 to avoid the hydrogen evolution reaction (equation 3) at anode which was harmful to coating.…”

“…The roughness and compactness of composite electrodeposits could be improved by ultrasonic assistance [24], high shear mixing [25], adding refiner [20] and alloying [26].…”

Developments in electrode design: structure, decoration and applications of electrodes for electrochemical technology

“…Zhou et al . have stressed the improved deposits achieved by dispersion of particles in electrolyte using high shear mixing, rather than the commonly used magnetic stirring . The importance of this approach is illustrated in Fig.…”

“…Zhou et al have stressed the improved deposits achieved by dispersion of particles in electrolyte using high shear mixing, rather than the commonly used magnetic stirring. 59 The importance wileyonlinelibrary.com/jctb of this approach is illustrated in Fig. 18, where the quality of electrolyte dispersion and deposit performance is considered for Ni-MoS 2 electrodeposits.…”