单层MoS_2悬浊液的制备及其摩擦学行为研究

Preparation and Tribological Behavior of Monolayer MoS_2 Suspended in Water

用插层法制备了单层MoS2在水中的悬浊液,采用X射线衍射仪、透射电子显微镜以及扫描电子显微镜表征了单层MoS2的结构,用四球长时摩擦磨损试验机考察了单层MoS2在水中的悬浊液的摩擦学行为.结果表明:MoS2经剥层-重堆过程处理后形成单层MoS2,单层MoS2在水中以单片或者多片重叠形式存在,其间距由0.615nm增大为0.622nm;所合成的单层MoS2悬浊液在一定添加量范围内表现出良好的减摩能力.这是因为其在钢球磨损表面生成含FeS的保护膜,而保护膜的剪切强度较低,因而表现出良好的减摩性能,但活性元素S易导致钢的过度腐蚀而使抗磨性能反而变差.

The aqueous suspension of monolayer molybdenum disulfide (MoS2) was prepared by means of exfoliating combined with restacking. The resulting monolayer MoS2 was characterized by means of powder Xray diffraction and transmission electron microscopy. The lubricating action of the aqueous suspension to a steelsteel pair was examined on a fourball machine, and the worn steel surface was analyzed by means of scanning electron microscopy and Xray photoelectron spectroscopy. As the results, the interlayer of MoS2 was expanded by 0.007 after exfoliatingrestacking process, and the MoS2 suspension composed of monolayer or several stacked layers showed good dispersion stability. The monolayer MoS2 suspended in water at proper concentrations was effective in improving the frictionreducing behavior, but it led to increased wear of the steel ball. This was because a lowershearstrength surface protective film composed of FeS and iron oxide was formed on the worn steel surface, while it was liable to be sheared and peeled off as wear debris. In other words, the surface protective film of lower shear strength accounted for the frictionreducing action of the aqueous suspension; while the erosive action of the active S in the suspension led to increased wear of the steel.