The effects of WS2 nanoparticles on the anticorrosion and tribological properties of electroless Ni–W–P coatings applied to aluminium

: In this research, Ni-W-P coatings, with and without WS 2 nanoparticles, were deposited on aluminium by the electroless method at 85 ± 1°C and a pH of 9.5. The deposition process was optimized by varying the concentration of WS 2 in the electroless bath from 0.1 to 0.4 g/l.Various analytical techniques were employed to assess the anticorrosion and tribological performance of the produced coatings. EDS analysis confirmed that WS 2 was co-deposited with Ni-W-P. The tungsten content increased from 4 wt.% in the sample without WS 2 to 11 wt.% in the Ni-W-P-(0.4)WS 2 coating. At the same time, the deposition rate and microhardness dropped from 11.02±0.01 μm/h to 8.78±0.12 μm/h and 612±2.7 HV to 476±1.6 HV, respectively. Based on SEM images, WS 2 nanoparticles were present on the surface and across the coatings; however, they were agglomerated. The electrochemical analyses demonstrated the positive effects of WS 2 on corrosion resistance, with the composite layer produced with 0.3 g/l WS 2 exhibiting the highest performance. Its superior resistance is evidenced by a corrosion current density of 0.214±0.02 μA·cm -2 approximately one-fourteenth the value measured for the Ni–W–P layer. Furthermore, it revealed the highest R ct (8109±145 Ω.cm 2 ) and R pore (21857±517 Ω.cm 2 ) along with the lowest CPE-T dl (17.1±1.3 μΩ -1 .S n .cm -2 ) and CPE-T coat (5.85±1.3 μΩ -1 .S n .cm -2 ) values. Moreover, the Ni–W–P–(0.4)WS 2 coating demonstrated the lowest friction coefficient of all samples investigated, confirming that WS 2 acts as a solid lubricant.