Hydrothermal Synthesis of MoS2 into Flame-Sprayed Ni60 Coating towards Superior Tribological Performance

Although flame-sprayed Ni60 coatings are widely used for the surface wear protection of mechanical parts, they have intrinsic shortcomings such as the high porosity and the lack of self-lubricating performance. In this work, MoS2 was introduced into the flame-sprayed Ni60 coating via hydrothermal synthesis, and the microstructure and tribological properties of the fabricated Ni60/MoS2 composite coating were studied. Microstructure observation of coatings shows that MoS2 in situ grew in the flame-sprayed Ni60 coating, both along the wall of internal pores/gaps and on the coating surface, leading to the significantly decreased coating porosity. The friction and wear tests show that the steady friction coefficient of the Ni60/MoS2 composite coating was about 0.22, which is 75% lower than that of the Ni60 coating (about 0.88). The wear rate of the Ni60/MoS2 composite coating after the 1 h wear test was about 1.22 x 10(-7) mm(3)N(-1) m(-1), reducing significantly compared to that of the Ni60 coating (2.16 x 10(-7) mm(3)N(-1) m(-1)). The superior tribological performance of the Ni60/MoS2 composite coating was attributed to the synergistic action of the self-lubricating MoS2 and the wear-resistant Ni60.