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

同时观察了白云母的原子尺度地形图像和原子尺度侧向力显微镜(LFM)图像。然后，从侧向力和滑动引起的表面原子形貌变化两个方面对原子磨损现象进行了评价。当载荷超过100nN时，在无损伤的云母表面形成凹槽。云母表面的磨损量约为1 nm，相当于从一个解理面表面到紧靠其下的解理面表面的深度。利用这种磨损机理，利用原子力显微镜(AFM)对白云母等层状晶体结构材料进行了原子级机械加工。加工在一定的临界载荷下开始，加工深度随载荷的增加而离散增加。断裂易发生在SiO_4-K和K-SiO_4界面的两个解理面上。评估了加工深度对载荷的依赖关系。随着载荷的增加，磨槽深度增大。加工侧向力由顶梁的扭转估计，分为犁削力和摩擦力。犁削力与加工深度成正比。针尖的几次机械滑动通过从表面去除钾而产生1 nm深的凹槽，钾对应于从SiO_4顶部表面到其下下一SiO_4层顶部表面的距离。采用分步机械滑动的方法加工了一种深度为1 nm的四阶凹槽。观察到了对应于SiO_4基面的凹槽各台阶表面的原子图像。然后对字母NIT(比例尺2000X600X1 nm)进行机械尖端滑动处理。

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.