Atomic scale wear of layred crystal structure material by atomic force microscope

点击翻译按钮获取中文摘要

Atomic-scale topographic images and atomic-scale lateral force microscope (LFM) images of muscovite mica were observed simultaneously. Then, the atomic wear phenomenon was evaluated from lateral force and surface atomic topographic changes caused by sliding. Above about 100 nN load, grooves were formed on the damage-free mica surface. Wear about one nm deep in the mica surface corresponds to the depth from the surface of one cleavage plane to the surface of the cleavage plane immediately beneath it. By applying this wear mechanism atomic-scale mechanical processing of layred crystal structure materials such as muscovite mica was performed using an atomic force microscope (AFM). Processing began at a certain critical load, and the processing depth increased discretely with load. Fracture easily occurred at the two cleavage planes of SiO_4-K and K-SiO_4 interfaces. The processing depth dependence on load was evaluated. The depth of the wear grooves increased with load. Processing lateral force estimated from the torsion of the tip beam was divided into plowing force and friction force. The plowing force is proportional to processed depth. Several cycles of mechanical sliding of the tip generated a 1-nm-deep groove by removing potassium from the surfaces which corresponded to the distance from the top surface of SiO_4 to the top surface of the next SiO_4 layr beneath it. A groove with four steps of one-nm depth was processed by stepwise mechanical sliding. Atomic images of each step surface of the groove corresponding to the SiO_4 basal plane were observed. Then the letters NIT (scale 2000X600X1nm) was procesed by mechanical tip sliding.