Velocity dependence and rest time effect on nanoscale friction of ultrathin films at high sliding velocities
Velocity dependence and rest time effect on nanoscale friction of ultrathin films at high sliding velocities
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DOI：
10.1116/1.2435381
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发表时间：
2007-07
期刊：
影响因子：
--
通讯作者：
Z. Tao;B. Bhushan
中科院分区：
文献类型：
--
作者：
Z. Tao;B. Bhushan
微/纳机电系统的器件和部件常常在高速滑动速度下工作，这就需要研究高速下的摩擦。在本研究中，利用超高速和高速台架研究了高达2×10~5μm/S的硬质类金刚石碳膜、软质全氟十二烷基三氯硅烷和全氟聚醚薄膜的摩擦速度依赖性和静止时间对摩擦的影响。摩擦的速度依赖关系随着薄膜的不同而不同，涉及不同的机制，包括固-固相互作用引起的粘着，弯月面桥形成的粘着，原子尺度的粘滑，接触的粗糙/分子的高速碰撞，相变/尖端跳跃，以及粘弹性剪切。摩擦随停留时间的增加是由于亲水性表面的水弯月桥的持续生长和形成，以及软膜的持续变形造成的。
Micro∕nanoelectromechanical system devices and components often operate at high sliding velocities, and it requires the investigation of friction at high velocities. In this study, the velocity dependence of friction and the rest time effect on friction of hard diamondlike carbon films, soft perfluorodecyltrichlorosilane, and perfluoropolyether films were investigated up to 2×105μm∕s using an ultrahigh velocity stage and a high velocity stage. The velocity dependence of friction was found to vary with films and involve different mechanisms including adhesion due to solid-solid interaction, adhesion due to formation of meniscus bridges, atomic-scale stick slip, high velocity impact of the contacting asperities∕molecules, phase transformation∕tip jump, and viscoelastic shear. The increase in friction as a function of rest time was caused by continued growth and formation of water menisci bridges for the hydrophilic surfaces and continued deformation of soft films.