Wear resistance of superior structural WS2–Sb2O3/Cu nanoscale multilayer film

• Novel kinds of WS2–Sb2O3/Cu nanoscale multilayer films were prepared.
• The co-incorporation of Sb2O3 dopant and thin Cu sublayer could induce WS2 amorphization.
• The dense multilayer film possessed high hardness, high H3/E2 and improved wear resistance.
• Two kinds of typical model of wear mechanism were introduced.

Transition metal dichalcogenides (TMDs) with layered structure exhibit very low friction coefficient but poor wear resistance in vacuum environments. To develop high wear resistance of WS2 film, its nanostructure was optimized by co-introducing of Sb2O3 dopant and Cu sublayer using sputtering technique. Effects of co-doping on film nano/microstructure, mechanical and tribological performance were investigated by GIXRD, FESEM, HRTEM, nano-indentation tester, AFM, 3D non-contact surface mapping profiler, scratch tester and vacuum ball-on-disk tribometer. The results showed that the growth of WS2 columnar platelets could be restricted by co-introducing of Sb2O3 dopant and thin Cu sublayer (about 1.6 nm), but not single-doping of even 10.0 at.% Sb2O3, leading to formation of amorphous WS2 phase. As compared to the loose WS2–Sb2O3 and pure WS2 films, the dense multilayer films possessed high hardness and high H3/E2, and those maximum values were 6.3 GPa and 2.7 × 10− 2 GPa, respectively. The doping 10.0 at.% Sb2O3 could double the film wear life to 2.7 × 105 cycles in vacuum under high Hertzian contact pressure (about 1.0 GPa), and further introduction of Cu sublayer would make the multilayer film much longer wear life about to 1.1 × 106 cycles. Wear mechanisms were discussed in terms of wear track morphology after different sliding cycles.

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