Ni-P-carbon nanotubes (Ni-P-CNTs) and Ni-P-
inorganic fullerene-like WS_2 (Ni-P-(IF-WS_2)) composite coatings were prepared
by electroless plating. The morphologies and microstructures of the CNTs and IF-WS_2 nanoparticles were analyzed by means of scanning electron microscopy, transmittance electron microscopy, and X-ray diffraction, while the phase structure and composition of the resulting composite coatings were characterized by means of X-ray diffraction and elemental analysis. The friction and wear behaviors of the self-mated pairs of the resulting composite coatings were investigated on an MHK-500 ring-on-block friction and wear tester under the lubrication of a mechine oil. It was found that the electroless Ni-P-CNTs and Ni-P-(IF-WS_2) composite coatings recorded much better friction-reducing and antiwear properties than the Ni-P and Ni-P-graphite coastings. The significant improvement in the tribological properties of the Ni-P-CNTs was attributed to the excellent reinforcing effect and self-lubricity of the CNTs of coaxial graphitic nanotube structures. In a similar manner, the nested hollow inorganic fullerene-like structure of IF-WS_2 nanoparticles and its rolling effect during the friction process accounted for the excellent tribological performance of Ni-P-(IF-WS_2) composite coating.