Micromechanics of friction: effects of nanometre-scale roughness
Micromechanics of friction: effects of nanometre-scale roughness
复制标题
DOI：
10.1098/rspa.2007.0364
复制
发表时间：
2008-05-08
影响因子：
3.5
通讯作者：
Kim, Kyung-Suk
中科院分区：
文献类型：
--
作者：
Li, Qunyang;Kim, Kyung-Suk
固体表面上的纳米级粗糙度对摩擦具有显著影响，因为表面间力主要在摩擦接触中的纳米级间隙距离内起作用。为了研究纳米级粗糙度的影响，进行了两个新的原子力显微镜摩擦实验，每个实验都使用金表面滑动。在云母表面作为代表摩擦系统。在其中一个实验中，一个柱状的单一纳米粗糙金被用来测量分子水平的摩擦行为。对于直接金云母接触，测得的粘附摩擦应力为264 MPa，分子摩擦因子为0.0108。纳米粗糙体在接触中变平，尽管其在该长度尺度下的硬度估计为3.68 GPa。人们发现，这样的高压可以达到冷凝水毛细力的帮助下。在第二个实验中，一个微米级的粗糙度与纳米级的粗糙度表现出一个单一的粗糙的摩擦响应。然而，表观摩擦应力，40.5 MPa，远低于Hurtado-Kim模型预测的208 - 245 MPa。此外，在摩擦过程中，多个纳米微凸体被压扁，表现出负载和滑动历史依赖的摩擦行为。
Nanometre-scale roughness on a solid surface has significant effects on friction, since intersurface forces operate predominantly within a nanometre-scale gap distance in frictional contact. To study the effects of nanometre-scale roughness, two novel atomic force microscope friction experiments were conducted, each using a gold surface sliding against a. at mica surface as the representative friction system. In one of the experiments, a pillar-shaped single nano-asperity of gold was used to measure the molecular-level frictional behaviour. The adhesive friction stress was measured to be 264 MPa and the molecular friction factor 0.0108 for a direct gold mica contact. The nano-asperity was flattened in contact, although its hardness at this length scale is estimated to be 3.68 GPa. It was found that such a high pressure could be reached with the help of condensed water capillary forces. In the second experiment, a micrometre-scale asperity with nanometre-scale roughness exhibited a single-asperity-like response of friction. However, the apparent frictional stress, 40.5 MPa, fell well below the Hurtado-Kim model prediction of 208 245 MPa. In addition, the multiple nano-asperities were flattened during the frictional process, exhibiting load-and slip-history-dependent frictional behaviour.