Abstract

The friction coefficient, an important parameter to evaluate the dynamic properties of friction pairs, has been widely used in macro engineering fields. However, it is probably inappropriate to characterize the tribological properties at the nanoscale due to the strong size effect, and the conventional formula cannot reveal its determinants owing to its oversimple form. Therefore, in the present work, a new formula is deduced to overcome these shortcomings. The established formula for the friction coefficient considers the adhesion and discloses the relationship between the friction coefficient and the material properties of diamond. It effectively suppresses the dependency of the friction coefficient on the load, although such a dependency cannot be eliminated completely. Therefore, another new formula, independent of the loading force, is derived. Interestingly, the results indicate that the size effect is invariably observed in the friction coefficients derived from the three formulas due to different accumulation effects of debris atoms, which is verified by molecular dynamics simulations.

Graphic Abstract

中文翻译：

---

纳米级金刚石摩擦系数的载荷和尺寸效应

摘要

摩擦系数是评估摩擦副动力学特性的重要参数，已广泛应用于宏观工程领域。但是，由于其强大的尺寸效应，在纳米尺度上表征摩擦学特性可能是不合适的，并且由于其过于简单的形式，常规公式无法揭示其决定因素。因此，在本工作中，推导了克服这些缺点的新公式。建立的摩擦系数公式考虑了附着力，并揭示了摩擦系数与金刚石材料性能之间的关系。尽管不能完全消除这种依赖性，但它有效地抑制了摩擦系数对负载的依赖性。因此，另一个新公式，与加载力无关，派生。有趣的是，结果表明，由于碎片原子的累积效应不同，在三个公式得出的摩擦系数中始终观察到尺寸效应，这已通过分子动力学模拟得到了验证。

图形摘要