Evaluation of practical performance of molecularly thin lubricant films having textures of nano-plateaus and nano-recesses

为了评价紫外光辐照形成的纳米平台和纳米凹槽织构的全氟聚醚(PFPE)润滑膜的实用性能，阐明了这种织构的形成机理和在类金刚石(DLC)表面形成织构的最佳条件。为此，研制了一种超高灵敏度摩擦试验机。通过滑动耗尽和补给试验，发现这种织构润滑膜具有摩擦性能可调的独特优势。研究结果总结如下：1)纳米织构的形成机理I)实验方法：对涂覆在DLC磁盘表面的三种PFPE润滑剂(UV反应型、Fomblin AM型、极性；Zdol和非极性；Z)的辐照时间进行了优化，并比较了UV辐照的效果。此外，两种照射方法，即涂布润滑剂前后的紫外线照射，均被确认为…分子模拟方法：使用SMART蒙特卡罗方法，利用固体表面不规则引起的固体和液体分子相互作用的局部分布来再现润滑剂织构的形成。将分子动力学模拟应用于固/液界面，通过润滑剂分子的极性端基与固体表面的碳分子之间的相互作用势的局部分布再现了润滑剂织构的形成。2)纳米织构润滑膜的耗尽和补充的评价。从滑动试验的结果证实，In辐照提供了在不降低补给性能的情况下抑制耗尽的优点。3)超高灵敏度摩擦试验机的研制一种新型摩擦试验机是由空气轴承支承的精密圆盘转轴和内置直流电机驱动的精密圆盘转轴和由紧凑的具有位移放大机构的PZT驱动器驱动的精密滑动销钉加载机构组成的。获得了2.5μN的粘附力和4μN的摩擦力的高分辨率。较少

To evaluate practical performance of perfluoropolyether (PFPE) lubricant films having texture of nano-plateaus and nano-recesses formed by ultraviolet (UV) ray irradiation, we clarified the mechanism of formation of the texture and optimum conditions for forming the texture on diamond like carbon (DLC) surface. For this purpose, an ultra-high sensitive friction tester was developed. Based on the sliding-induced depletion and replenishment tests, the present textured lubricant film was found to have a special advantage of adjustable tribo-performances. The results are summarized as follows.1) Mechanism of formation of nano-texture i) Experimental approach: For three kinds of PFPE lubricants (UV reactive; Fomblin AM type, polar; Zdol and non-polar; Z) coated on DLC surfaces for magnetic disk use, the irradiation time was optimized and the effects of UV irradiation were compared. In addition, both of irradiation methods; UV irradiation after/before lubricant coating, were confirmed to be … More effective.ii) Molecular simulation approach : Using the smart Monte Carlo method, formation of lubricant texture was reproduced using a local distribution of solid and liquid molecules interaction caused by solid surface irregularity. Applying the molecular-dynamic simulation to solid/liquid interface, formation of lubricant texture was reproduced using a local distribution of the interaction potential between polar end groups of lubricant molecules and carbon molecules of solid surface.2) Evaluation of depletion and replenishment of nano-texture lubricant film. From the results of the sliding test, IN irradiation was confirmed to provide advantages of suppressed depletion without decreasing replenishment performance. Comparing parallel/perpendicular patterns and no pattern, it was found that, as for depletion, the with-pattern case was equivalents to the no-pattern case, while as for depletion, the relationships where the perpendicular case ≒ no pattern>the parallel case held.3) Development of ultra-high sensitive friction tester A new friction tester was constituted by an accurate disk rotation spindle supported by an air bearing and driven by a build-in direct DC motor, and a precise sliding pin-loading mechanism driven by a compact PZT actuator with displacement magnification mechanism. This attained high resolutions of 2.5 μN for the adhesion force and 4μN for the friction force. Less