Gao G T, Mikulski Paul T, Harrison Judith A
Chemistry Department, United States Naval Academy, Annapolis, Maryland 21402, USA.
J Am Chem Soc. 2002 Jun 19;124(24):7202-9. doi: 10.1021/ja0178618.
Classical molecular dynamics simulations have been conducted to investigate the atomic-scale friction and wear when hydrogen-terminated diamond (111) counterfaces are in sliding contact with diamond (111) surfaces coated with amorphous, hydrogen-free carbon films. Two films, with approximately the same ratio of sp(3)-to-sp(2) carbon, but different thicknesses, have been examined. Both systems give a similar average friction in the load range examined. Above a critical load, a series of tribochemical reactions occur resulting in a significant restructuring of the film. This restructuring is analogous to the "run-in" observed in macroscopic friction experiments and reduces the friction. The contribution of adhesion between the probe (counterface) and the sample to friction was examined by varying the saturation of the counterface. Decreasing the degree of counterface saturation, by reducing the hydrogen termination, increases the friction. Finally, the contribution of long-range interactions to friction was examined by using two potential energy functions that differ only in their long-range forces to examine friction in the same system.
已进行经典分子动力学模拟，以研究氢端接金刚石（111）对偶面与涂有无定形无氢碳膜的金刚石（111）表面滑动接触时的原子尺度摩擦和磨损。研究了两种具有大致相同的sp(3)与sp(2)碳比例但厚度不同的薄膜。在研究的载荷范围内，两个系统给出了相似的平均摩擦力。在临界载荷以上，会发生一系列摩擦化学反应，导致薄膜发生显著的结构重组。这种结构重组类似于宏观摩擦实验中观察到的“磨合”，并降低了摩擦力。通过改变对偶面的饱和度，研究了探针（对偶面）与样品之间的粘附对摩擦的贡献。通过减少氢端接来降低对偶面饱和度，摩擦力会增加。最后，通过使用仅在长程力方面不同的两个势能函数，在同一系统中研究长程相互作用对摩擦的贡献。
