2004 Fiscal Year Final Research Report Summary
Friction control by means of self-assembled nano-lubricant film
| Project/Area Number |
14205029
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
設計工学・機械要素・トライボロジー
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| Research Institution | NATIONAL INSTITUTE OF ADVANCED INDUSTRIAL SCIENCE AND TECHNOLOGY |
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Principal Investigator |
KATO Takahisa National Institute of Advanced Industrial Science and Technology, 先進製造プロセス研究部門, 総括研究員 (60152716)
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| Co-Investigator(Kenkyū-buntansha) |
MASUKO Masabumi Tokyo Institute of Technology, Graduate School of Science and Engineering, Professor, 大学院・理工学研究科化学工学専攻, 教授 (60111663)
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| Project Period (FY) |
2002 – 2004
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| Keywords | self-assembled monolayer / friction control / bonded layer / mobile layer / diamond-like carbon / lifetime / three-parameter model |
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| Research Abstract |
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 surfaces
It 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
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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 property
The 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 method
We 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
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