Effect of MoS2 nanoparticles on the properties of Ni-W-SiC composite coatings

Abstract

To improve the comprehensive protection performances of Ni-W-SiC composite coatings, we successfully manufactured Ni-W-SiC-MoS2 composite coatings using an electrodeposition technique on a 7075 aluminum alloy surface. We analysed the changes in microhardness, wear resistance, corrosion resistance, surface morphology and roughness of the composite coatings upon the addition of MoS2 nanoparticles. A microscopic characterisation of the Ni-W-SiC-MoS2 coatings was carried out by scanning electron microscope and atomic force microscope. The elemental composition was analysed by energy dispersive spectroscopy. The grain size was calculated by X-ray diffraction. The microhardnesses of the Ni-W-SiC-MoS2 composite coatings were evaluated by a microhardness tester, the wear resistance was tested by a rotary friction tester, and the corrosion resistance was evaluated using an electrochemical workstation. The tests indicate that the addition of MoS2 nanoparticles has significant effects on the micromorphology and grain size of Ni-W-SiC,and that they can uniformly codeposit with SiC nanoparticles in the Ni-W coating, exerting a synergistic effect on the improvement in the performance of the composite coating. When the amount of added MoS2 is 8 g/L, the Ni-W-SiC-MoS2 coating has the smallest grain size and highest microhardness (917.6 HV). Its corrosion resistance is considerably improved compared to that of the Ni-W-SiC coating. When the MoS2 concentration is 6 g/L, the Ni-W-SiC-MoS2 coating has the highest content of MoS2 nanoparticles, the friction coefficient reaches the minimum (0.24), and the wear resistance is best.