论文标题:碳纳米管摩擦性能的分子动力学模拟
Molecular-Dynamics Simulation of the Friction of the Carbon Nanotube
论文作者
论文导师 陈云飞,论文学位 硕士,论文专业 机械设计及理论
论文单位 东南大学,点击次数 97,论文页数 51页File Size11967K
2006-03-01论文网 http://www.lw23.com/lunwen_102371757/
carbon nanotubes;molecular-dynamics simulation;the friction coefficient;Stick-slip;superlubric state
碳纳米管由于特殊的空间结构和突出的物理性能而广泛用于各类扫描探针显微镜。本文采用分子动力学模拟的方法模拟了碳纳米管在金刚石基底和氩基底上的滑动过程以及碳纳米管在铺上氩的金刚石基底上的滑动过程。通过对模型在不同滑移方向的模拟,以及摩擦系数与温度、滑动速度、载荷的关系,表明碳纳米管在金刚石基底滑动时:摩擦系数μ随着温度、载荷和滑动速度的变化几乎不变。并且在这些情况下计算出的摩擦系数μ都很小,只有0.001的量级,我们认为碳纳米管在金刚石基底上滑动时出现了超固体润滑现象。其产生的主要原因我们认为是当碳纳米管在金刚石基底上滑动时,由于上表面(碳纳米管)的晶格方向与下表面(金刚石)的晶格方向为非相称接触而引起的。碳纳米管在金刚石基底以及氩基底上滑动滑动时,碳纳米管受到的摩擦力产生了明显的跃动现象,我们认为微观状态下,上、下表面间的晶格随着滑移而导致的相对位置变化是产生跃动现象的根本原因。当碳纳米管在铺上氩的金刚石基底上的滑动时,摩擦力并没有出现跃动和超固体润滑现象。这主要是因为氩对碳纳米管的影响。在所有滑动过程中碳纳米管几乎无磨损,针对这种现象文章给出了解释:这一方面是因为碳纳米管与金刚石基底和氩基底之间的超固体润滑,另一方面是因为碳纳米管特殊的空间结构和突出的物理性能。
Carbon nanotube has been expected to be a suitable material to the apex of scanning probe microscopy (SPM) tips because of its unique physical properties and special structures. Molecular-dynamics (MD) simulation method is used in this presentation to investigate the friction between carbon nanotube and diamond and Ar surface. The friction which occurs when carbon nanotube and surface are placed in sliding contact is investigated for sliding in different directions, as a function of applied load, temperature, and sliding velocity. The friction coefficientμis approximately independent of sliding velocity and applied load when carbon nanotube is sliding on the diamond surface. In these conditions, The friction coefficient is only equal 0.001.We think it is the superlubric state. The main reason is the uncommensurate contact between nanotube’s crystal orientation and diamond’s crystal orientation. Stick-slip of friction is found when carbon nanotube is sliding on the surface. We think the change of atomic-lattice’s position is the main reason. Because of effecting of Ar,stick-slip and superlubric is not found when nanotube is sliding on the suface(Ar spreaded on the diamond surface) .Nanotube is nearly free from wear at all the sliding process because of its unique physical properties and special structures and superlubric state.
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