2000 Fiscal Year Final Research Report Summary
Role of Nanometer Roughness Structures in Mixed Thin-Film Lubrication
| Project/Area Number |
10450066
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| Research Category |
Grant-in-Aid for Scientific Research (B).
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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 | KYUSHU UNIVERSITY |
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Principal Investigator |
SUGIMURA Joichi KYUSHU UNIVERSITY, Faculty of Engeneering, Ass. Prof., 大学院・工学研究院, 助教授 (20187660)
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| Co-Investigator(Kenkyū-buntansha) |
GONDO Seigo KYUSHU UNIVERSITY, Faculty of Engeneering, Assistant, 大学院・工学研究院, 助手 (50037975)
YAMAMOTO Yuji KYUSHU UNIVERSITY, Faculty of Engeneering, Prof., 大学院・工学研究院, 教授 (10037997)
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| Project Period (FY) |
1998 – 2000
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| Keywords | Tribology / Mixed lubrication / Thin Film / Surface Roughness / Lubricant / Sputtering / Ultra-thin FIlm Interferometry / Molecular Dynamics |
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| Research Abstract |
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
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Research Products
(10 results)
