Abstract: MoS2 was prepared by a hydrothermal method at a relatively lower temperature(200 ℃) and shorter reaction duration(24 h). The resulting product samples were investigated by means of transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). The lubricating behavior of the prepared MoS2 sample as an additive in paraffin oil was examined on an MPX-2000 friction and wear tester. The worn steel surface was analyzed by means of Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS) to investigate the lubricating mechanism of the synthetic MoS2 in the paraffin oil. It was found that the synthetic MoS2 as an additive in the paraffin oil showed better friction-reducing and antiwear ability than a commercial MoS2 of a diameter 3～5 μm in the same base stock and was more suitable for the situation of heavy load and long time running. MoS2 functioned to reduce the friction and wear of the steel-steel system by forming a transfer film on the worn steel surface but not by tribochemical reaction and diffusion and permeation therewith.

Key words: Hydrothermal synthesis, MoS₂, Lubricating behavior