Surfactant-assisted electrodeposition of Au–Co/WS2 self-lubricating coating from WS2 suspended cyanide electrolyte

In this study, Triton X-100 was used as the WS 2 dispersion agent in the Au–Co cyanide electrolyte to deposit Au–Co/WS 2 composite coatings . Probe sonication was applied to exfoliate the commercial WS 2 powders to produce thinner and smaller WS 2 flakes, which improved the stability of the WS 2 particles in the electrolyte. According to the electrochemical analyses , the effects of adding Triton X-100 and WS 2 particles to the electroplating process were investigated. Through material characterizations, WS 2 particles were proved to be compounded into the Au–Co matrix and showed clearly {002} preferred orientation due to their flake structures. Tribological tests were performed under dry condition in 10 −3 Pa vacuum against stainless steel 316L balls with diameters of 3 mm and a normal contact force of 2 N. The Au–Co/WS 2 composite coatings that developed showed the minimum coefficient of friction and wear rate of 0.05 and 8 × 10 −6 mm 3 /N·m, which are 5 times and 3 times lower than the Au–Co reference coating, respectively.