Petzold Christiane, Koch Marcus, Bennewitz Roland
INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken, Germany.
Beilstein J Nanotechnol. 2018 Jun 5;9:1647-1658. doi: 10.3762/bjnano.9.157. eCollection 2018.
Friction force microscopy was performed with oxidized or gold-coated silicon tips sliding on Au(111) or oxidized Si(100) surfaces in ultrahigh vacuum. We measured very low friction forces compared to adhesion forces and found a modulation of lateral forces reflecting the atomic structure of the surfaces. Holding the force-microscopy tip stationary for some time did not lead to an increase in static friction, i.e., no contact ageing was observed for these pairs of tip and surface. Passivating layers from tip or surface were removed in order to allow for contact ageing through the development of chemical bonds in the static contact. After removal of the passivating layers, tribochemical reactions resulted in strong friction forces and tip wear. Friction, wear, and the re-passivation by oxides are discussed based on results for the temporal development of friction forces, on images of the scanned area after friction force microscopy experiments, and on electron microscopy of the tips.
在超高真空中，使用氧化或镀金的硅尖端在Au(111)或氧化的Si(100)表面上滑动进行摩擦力显微镜实验。与粘附力相比，我们测量到的摩擦力非常低，并且发现横向力的调制反映了表面的原子结构。将力显微镜尖端保持静止一段时间不会导致静摩擦力增加，即对于这些尖端和表面对，未观察到接触老化现象。去除尖端或表面的钝化层，以便通过静态接触中化学键的形成实现接触老化。去除钝化层后，摩擦化学反应导致强大的摩擦力和尖端磨损。基于摩擦力随时间变化的结果、摩擦力显微镜实验后扫描区域的图像以及尖端的电子显微镜图像，讨论了摩擦、磨损和氧化物的再钝化现象。
