1997 Fiscal Year Final Research Report Summary
Synergistic effect on spacetribology in the low earch orbit
| Project/Area Number |
08455082
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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 | Osaka University |
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Principal Investigator |
OHMAE Nobuo Faculty of Engineering, Osaka University, Associate Professor, 工学部, 助教授 (60029345)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMURA Takayoshi Faculty of Engineering, Osaka University, Research Associate, 工学部, 助手 (90252600)
TAGAWA Masahito Faculty of Engineering, Osaka University, Research Associate, 工学部, 助手 (10216806)
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| Project Period (FY) |
1996 – 1997
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| Keywords | atomic oxygen / space environmental effect / tribology / low earth orbit / synergy / UV / MoS_2 |
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| Research Abstract |
The purpose of this project is to clarify the synergistic effect of atomic oxygen (AO) and the other environmental factors, such as ultraviolet (UV) light or X-rays, in the tribology of satellites used in low earth orbital (LEO) environment. An ion beam type and a laser induced breakdown type AO sources are used in this study to generate energtic AO beam in the laboratory. The research results obtained in this project are as follows :
1. The reaction efficiency of AO with the polyimide film formed by a spin-coating technique is influenced by UV irradiation. Only in the simultaneous irradiation of AO and UV,significant mass loss and CO_2 formation is detected. This research result suggests the photo-assisted chemical reaction of the functional groups such as carbonyl, which absorbs UV light, occurs at the AO bombarded polymer surfaces where carbonyl is formed by AO attacks.
2. When AO hits MoS_2 (0001) surface, So is formed. This volatile product is detected by a quadrupole mass spectrometer during AO beam exposure on MoS_2 (0001). However, the rate of evaporation is not linear with time. This is probably due to the low diffusion rate of AO into the MoS_2 bulk, i.e., reaction is limited only at the very surface region where only limited amount of S is existed.
3. Tribological properties of MoS_2 (0001) is not suffered by AO attack very much. We see maximum 40% increase of initial friction after AO exposure. However, similar effect is also observed even before AO exposure. Certain percentage of this effect is dur to wear track formation. This effect obviously depends on the sliding system and materials' constants. We need to know how much AO influences to the actual sliding component, because the effect of AO on the tribological property of sputtered MoS_2 may be different with single crystal. Further research on this point must be necessary.
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[Publications] Ohmae N., Tagawa M., Kinoshita H., Ikeda J., Arita M., Kishi K., Shibata M.: "Space Tribological Activities in Japan, -Laboratory Data and Flight Experiment aboard SFU/EFFU" Proceedings of the 7th International Symposium on Materials in a Space Environment, June 1997, Toulous, France. ESASP399. 387-389
Description
「研究成果報告書概要(欧文)」より
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