Effect of current density, MoS₂content and bath agitation on tribological properties of electrodeposited nanostructured Ni-MoS₂composite coatings

Abstract

Nanostructured nickel coatings with molybdenum disulphide particles were electrodeposited to form composite coatings. Three different current densities, i.e. 3, 5 and 7 A/dm 2 were investigated initially. The best results were obtained with 5 A/dm 2 for codeposition of nanostructured Ni-MoS 2 composite coatings. With the addition of 1-4 g/L molybdenum disulphide to the bath, the weight percentages of MoS 2 particles in the coatings were 23-38%. This increase of MoS 2 content was accompanied with decrease in friction coefficient of the coatings from 0.35 to 0.08. Wear resistance of the coatings was increased with increasing MoS 2 content and the weight loss was decreased from 1.4 to 0.7 mg. Hardness was decreased from 585 to 400 VHN with increasing the MoS 2 content. By increasing bath agitation speed up to 150 rpm, more MoS 2 particles were embedded in the matrix and the coatings showed better wear resistance. However, increase of agitation speed from 150 to 200 rpm caused a decrease of MoS 2 particles in the nickel matrix due to the turbulent motion of particles in the bath. Overall, it was shown that the lubricating effect of MoS 2 in the coating was more influential than the nanocrystallinity of the nickel matrix in improving tribological properties of these composite coatings.

Interfacial and Tribological Characteristics of MoS2 on Ni Under Nanoindentation and Nanoscratch

“…Additionally, an increase in the compound improves the lubricating effect with an increase in the quantity of particles integrated into the coatings. Previous results [25][26][27][28] mainly explain the improvement in the lubricating performance of coatings. In addition, the abrasive tip is prone to adhesive wear and material detachment; which plowing and pile-up of stacked atomic is leading to high friction.…”

Synthesis and wear characterization of Al7075/molybdenum disulfide/zirconium diboride hybrid composites

“…Additionally, Al7075 alloy wear loss is decreasing with the adding molybdenum disulfide as well as zirconium diboride particles. Molybdenum disulfide particles reduce wear loss due to their lubricating nature whereas zirconium diboride particles reduce due to their increased hardness as per Archard's wear law [18,38]. Al7075 + 3 vol % molybdenum disulfide + 9 vol % zirconium diboride hybrid composite shows the lowest wear loss among all compositions.…”

Characterization and Wear Behaviors of Electrodeposited Ni-MoS2/SiC Composite Coating

“…Ni ions prefer to nucleate on the particles' surfaces rather than around the particles, resulting in nodular structures. Shourije et al [43] and He et al [31] reported the strong influence of conducting particles on the local current distribution and its growth kinetics during the electrodeposition process. In addition, the MoS 2 particles enhance the denseness of the composite coating structure.…”