Role of Nanometer Roughness Structures in Mixed Thin-Film Lubrication

本研究项目探索了在混合薄膜润滑条件下，纳米表面粗糙度对各种分子结构流体的超薄润滑膜形成的可能影响。取得了以下研究成果：1.通过改变溅射功率、衬底温度和气压，在玻璃圆盘上制备了不同表面粗糙度和粗糙度结构的薄膜。表面生长的简单数值模拟也从理论上说明了这些溅射条件的影响。设计并制作了结合超薄膜干涉技术的纳米润滑膜厚度测量试验台，利用该试验台对集中滑动和滚动接触下的纳米润滑膜进行了测量，测量精度达到2 nm。测量表明，小于15纳米的润滑膜的形成取决于流体分子的大小和结构。极摩尔…在较光滑的表面上，较多的CuLE分子倾向于形成多层吸附膜，而在较粗糙的表面上，非极性分子倾向于形成润滑膜。前者与吸附向流体动力成膜的转变有关，后者与接触上游的流体供给有关。提出了荧光薄膜观测中存在的几个问题，并提出了解决这些问题的方法。对恒加速度下EHL膜厚的理论考虑表明，纳米级膜依赖于接触上游较远位置的润滑剂供应，而不是考虑厚得多的流体动力膜。润湿性测量表明，流体在二氧化硅表面的锯切速度取决于流体的分子结构；极性分子在较光滑的表面上扩散得更快，而非极性分子在较粗糙的表面上扩散得更快。流体扩散的分子动力学模拟表明，流体行为与纳米表面粗糙度有关。较少

This research project explored possible effects of nanometer surface roughness on the formation of very thin lubricating films of fluids of various molecular structures under the mixed thin-film lubrication regime. The following results were obtained.1. Surfaces of different roughness magnitudes and roughness structures were produced by changing sputter power, substrate temperature and argon pressure in double-layer sputter coating on glass disk specimens. The effects of these sputter conditions were also shown theoretically by simple numerical simulation of surface growth.2. Film thickness measurement rig incorporating ultra-thin film interferometry were designed and manufactured, and by using the rig, nanometer lubricating films under concentrated sliding and rolling contact were measured with an accuracy of 2 nm.3. The measurement demonstrated that the formation of lubricating films of less than fifteen nanometers depended on the size and the structure of fluid molecules. Polar mole … More cules tended to form multi-layer adsorption film on smoother surfaces, whereas non-polar molecules tended to form lubricating films on rougher surfaces. The former was related with transition from adsorption to hydrodynamic film formation, while the latter was related with fluid supply at upstream of the contact.4. Several problems in the observation and measurement of thin films with fluorescence, and methods to overcome the problems were developed.5. Theoretical consideration on ehl film thickness under constant acceleration suggested that nanometer order films depends on lubricant supply at farther upstream of the contact than those considered with much thicker hydrodynamic films.6. Measurement of wetting revealed that saread speed of fluids on silica surfaces depended on fluid molecular structure ; polar molecules spread faster on smoother surfaces, while non-polar molecules spread faster on rougher surfaces.7. Molecular dynamics simulation of spread of fluids suggested the dependence of fluid behavior on nanometer surface roughness. Less