Graphite is typically regarded as a solid lubricant, but its effectiveness as a lubricant can vary depending on environmental conditions. Since macroscopic contact with graphite involves both basal planes and step edges of micro- or nano-crystalline particulates, it is critical to understand their individual contributions of each to the environment-dependent friction. To that end, this study used atomic force microscopy with a Si probe to investigate the effect of adsorption from the gas phase of water and n-pentanol on the nanoscale friction of the basal plane and step edge of graphite. The results showed that as the ambient humidity increases, friction on the basal plane increases monotonically, while friction at the step edge first increases and then decreases. Additionally, when n-pentanol is adsorbed, the friction of both basal plane and step edge decreases. These findings could be correlated with the isotherm and structure of the adsorbed molecules in the sliding interfaces, which alters the degree of commensurate interactions between the probe and the basal plane, as well as the transient chemical interactions between the probe and the step edge.

石墨通常被视为固体润滑剂，但其作为润滑剂的有效性会因环境条件而异。由于与石墨的宏观接触涉及基面和微晶或纳米晶颗粒的阶梯边缘，因此了解它们各自对环境相关摩擦的贡献至关重要。为此，本研究使用带有 Si 探针的原子力显微镜来研究水和正戊醇气相吸附对石墨基面和阶梯边缘的纳米级摩擦的影响。结果表明，随着环境湿度的增加，基面的摩擦力单调增加，而台阶边缘的摩擦力先增加后减小。此外，当正戊醇被吸附时，基面和阶梯边缘的摩擦力均减小。这些发现可能与滑动界面中吸附分子的等温线和结构相关，滑动界面改变了探针与基面之间的相应相互作用程度，以及探针与阶梯边缘之间的瞬态化学相互作用。