纳米二硫化钼作为机械油添加剂的摩擦学特性研究

Tribological Properties of MoS_2 Nanoparticles as Additive in a Machine Oil

由硫化钠和钼酸钠水溶液反应生成棕色三硫化钼膏状沉淀,将三硫化钼粉末干燥后在氢气保护气氛中于适宜温度下煅烧脱硫,制得了粒径为20～30nm的纳米MoS2颗粒.用X射线衍射仪和透射电子显微镜分析了MoS2纳米颗粒的相组成和微观形貌;利用四球摩擦磨损试验机测定了纳米MoS2作为N46机械油添加剂的摩擦学性能;采用X射线光电子能谱仪分析了磨痕表面元素的化学状态,用扫描电子显微镜观察了磨痕表面形貌,探讨了纳米MoS2的减摩抗磨机理.结果表明,同普通MoS2微粒相比,纳米MoS2更易发生化学反应并在钢球磨损表面形成含三氧化钼的表面膜,纳米MoS2添加剂的极压、抗磨和减摩性能优于普通MoS2.

The nanoparticles of molybdenum disulfide were prepared by heating molybdenum trisulfide precipitates obtained from the aqueous reaction of sodium sulfide and sodium molybdenate in hydrogen atmosphere. The crystallite composition and micro-morphology of the resulting MoS_2 nanoparticles were analyzed by means of X-ray diffraction and transmittance electron microscopy. The tribological behavior of the MoS_2 nanoparticles as additive in N46 machine oil was comparatively investigated with that of commercial micro-MoS_2 particulates on a four-ball machine. The chemical states of the elements on the worn steel surface under different lubricating conditions were determined on an X-ray photoelectron spectroscope, while the morphologies of the worn steel surfaces lubricated with different lubricant systems were observed on a scanning electron microscope. It was found that the MoS_2 nanoparticles had a grit size of 20-30 nm. They showed better friction-reducing, antiwear, and extreme pressure properties than the commercial micro-MoS_2 in the N46 machine oil. This could be attributed to the easier adsorption of the MoS_2 nanoparticles on the sliding steel surface and the formation of a molybdenum trioxide-containing lubricating and protective film thereon by the readily oxidation of the nanoparticles in the sliding process.