Microstructural, mechanical and tribological properties of carbon nanotubes reinforced plasma sprayed molybdenum disulphide composite coatings

The development of 1-Dimensional (1D) and 2-Dimensional (2D) materials have gained considerable attention towards achieving solid-state lubricity. Herein, we present the effect of carbon nanotubes (1D) reinforcement into the molybdenum disulphide (2D) coatings. Plasma sprayed MoS2 coatings reinforced with 2-4 wt% CNTs were fabricated using shroud plasma spraying over steel substrates. The shroud attachment envelops the plasma plume and cut down its exposure to surroundings, which minimizes the oxidation of MoS2 powder during spraying. The microstructural analysis revealed the presence of MoS2 and CNTs in the composite coating. The mechanical hardness and elastic modulus of MoS2 coating improved by 2-3 folds in the composite coating. In tribological performance, the coefficient of friction (COF) decreased from 0.13 to 0.07 in M2C coating. The wear weight loss was estimated as 0.89 +/- 0.07 mg, 0.18 +/- 0.02 mg and 0.39 +/- 0.03 mg for M, M2C and M4C coatings respectively. It can be attributed that tubular CNTs acted as bearing on MoS2 layers. This work opens an impressive stepping for the synergistic mixture of 1D (CNTs) and 2D (MoS2) material to obtain high-quality wear resistant coatings.