Friction control by means of self-assembled nano-lubricant film

研究的目的是了解HDI的摩擦学现象，特别是当头部飞行高度小于10 nm时。本文重点研究了超薄磁盘润滑膜的摩擦学特性和润滑纳米膜的优化设计。润滑膜必须同时具有粘接（固体表面）和流体特性，因此一个好的润滑膜由合适的粘接层和流动层组成。目的是研制低摩擦、高耐久性、高抗振动稳定性的双单层润滑膜极限润滑系统。非晶碳表面强键合碳氢化合物膜的气相沉积描述了用真空气相沉积法在碳表面沉积强键合碳氢化合物膜（1-癸醇和癸酸）。从接触角测试和x射线光电子能谱测量结果可以看出，气相沉积可以使端羟基或端羧基的碳氢化合物分子在碳表面形成强键合。它与碳表面羟基或羧基端基与不饱和电子之间的静电相互作用有关。讨论了摩擦测量的结果PFPE润滑膜的自疏性对磨损性能的影响在实际硬盘中出现近接触或接触滑块的情况下，PFPE润滑膜的作用就显得尤为重要。已知在固体表面固定有OH或COOH末端的PFPE单层膜表现出自疏性，并且PFPE分子在PFPE单层膜上粘附并形成液滴。对PFPE纳米润滑膜的稳定性进行了研究，结果表明，PFPE纳米润滑膜的脱湿表面具有较高的摩擦强度和较低的使用寿命等摩擦学特性。显微镜下的观察也表明，PFPE分子的液滴随着时间的推移而生长阐明了结合层和活动层的摩擦特性，提出了它们作为HD润滑剂的理想组合。研究还表明，结合层厚度和流动层厚度对PFPE纳米润滑膜的寿命有很大影响。除此之外，我们还澄清了PFPE纳米润滑膜被小玻璃球滑动时的摩擦痕迹，这些摩擦痕迹反映了移动层的磨损，其次是粘合层的磨损。我们现在的重点是利用固定在玻璃球上的声发射传感器进行声发射测量，分析纳米润滑膜的磨损过程。结果表明，通过对声发射数据进行精细处理，可以区分粘结膜和移动膜的磨损过程。声发射测量结果更明确了键合层和移动层的作用，强调了两者结合的重要性。少

The objective of the research is to understand the tribological phenomenon of HDI, particularly when the head flying height is smaller than 10 nm. The clarification of tribological characteristics of an ultra thin lubricant film on the magnetic disk and the optimum design of the lubricant nanofilm are focused on in this research. Lubricant film must have both adhesive (to solid surface) and fluidic characteristics thus a good lubricant film consists of suitable bonded and mobile layers. The development of ultimate lubrication system is aimed, which is made of bi-monolayer-lubricant film keeping low friction, high durability and high stability against vibration.1.Vapor deposition of strongly bonded hydrocarbon films on amorphous carbon surfacesIt is described that a deposition of strongly bonded hydrocarbon films (1-decanol and decanoic acid) on carbon surfaces by vacuum vapor deposition. From the results of contact angle tests and X-ray photoelectron spectroscopy measurements, we concl … More ude that the hydrocarbon molecules having hydroxyl or carboxyl end groups can be strongly bonded on carbon surfaces by vapor deposition. It is related to the electrostatic interaction between hydroxyl or carboxyl end groups and unsaturated electrons on carbon surfaces. The results of friction measurements are also discussed.2 An effect of autophobicity of PFPE lubricant film on wear propertyThe role of PFPE thin film becomes more important in case that near contact or contact slider is brought about in the actual HDD. It is known that a monolayer film of PFPE with OH or COOH ends fixed on a solid surface exhibits autophobicity and PFPE molecules on the PFPE monolayer cohere and make droplets. The stability of PFPE nano lubricant film is investigated and it is shown that the dewetted surface shows undeairable tribological characteristics such as higher friction and lower lifetime. It is also shown that the observation by microscope shows the droplets of PFPE molecules grows with time.3 Wear process observed by AE methodWe have clarified the frictional characteristics of bonded and mobile layers and proposed their desirable combination as HD lubricants. It was also shown that the lifetime of the PFPE nanolubricant film is strongly affected by the combination of bonded and mobile layer thicknesses. In addition to them we clarified that the frictional trace of PFPE nano lubricant film slid by a small glass ball using pin-on-disk tribotester or spin-stand configurations reflects the wear of mobile layer followed by the wear of bonded layer. We are now focusing on the analysis of the wear process of nanolubricant film using AE measurement using an AE sensor fixed on the glass ball. It is clarified that the wear process of the bonded and mobile films can be distinguished by an elaborate processing of the measured AE data. The results obtained by the AE measurements clarified more the roles of the bonded and mobile layers and emphasize the importance of the combination of them. Less