Improving tribological properties of (Zn–Ni)/nano Al2O3 composite coatings produced by ultrasonic assisted pulse plating

Electrodeposited Zinc-Nickel Nanocomposite Coatings

“…As expected, addition of nanoparticles to the coatings improve the overall hardness values, as demonstrated with an increase of 305 HV to 524 HV for ZnNi coatings with CeO 2 treated SiO 2 particles, an increase of 35 HV with the addition of TiO 2 particles in Praveen's work, a 300% increase in hardness with an incorporation of 11.2 wt % Al 2 O 3 particles in Zheng's work and noticeable increases in both Ataie's and Ghaziof's work with incorporation of Al 2 O 3 particles as well [27,29,32,37,47]. The improved microhardness is believed to be due to dispersive strengthening as the ceramic like particles (TiO 2 ) form a barrier to deformation commonly observed in metal matrix systems.…”

“…Uptake of the nanoparticles is of interest as varying concentrations of nanoparticles are found, dependent upon the character of the particle being added to the solution. ZnNi coatings with Al 2 O 3 incorporation were found to contain anywhere from trace Al 2 O 3 up to 8.9 wt % throughout the literature [12,[27][28][29][30][31][32][33]. Zinc-nickel coatings with TiO 2 incorporation were found to contain on average 80-85% Zn, 12-17% Ni and 1.25-2.5% Ti [35][36][37].…”

“…ZnNi-Al 2 O 3 /SiC coatings still follow an anomalous deposition route. Improved hardness and corrosion properties are observed with incorporation of Al 2 O 3 [12,27,29,32,46].…”

“…A review of the literature shows most studies being performed under acidic conditions [32-37, 39-40, 44, 46] with little work in alkaline conditions [12,42,48]. ZnNi-Al 2 O 3 coatings were predominantly deposited under acidic conditions (pH = 4, 4.9 and 5.0) with one group examining deposition at pH = 13 [12,[27][28][29][30][31][32][33]. The literature for the deposition of ZnNi-TiO 2 coatings was done under acidic conditions with pH = 2.5, 4 and 4.6 from a variety of groups [11,[34][35][36][37].…”

Metal-containing nanomaterials as lubricant additives: State-of-the-art and future development

“…Owing to the synergetic effect of more than one NP type, composites usually exhibit superior performance compared to individual NPs [136][137][138]. Thus, Cu/CeO 2 , Al 2 O 3 /SiO 2 , ZrO 2 /SiO 2 , and (Zn-Ni)/nano Al 2 O 3 composite NPs were used as energy-efficient lubricant additives [139]. Lubricant additives such as nano-Ag/ multi-wall carbon nanotubes [140] and silver NPdecorated graphene [141] should be mentioned.…”