2015 Fiscal Year Annual Research Report
Study of the Tribological Properties of Graphene and Related Materials Under Extreme Environments
| Project/Area Number |
15H06471
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| Research Institution | Kyushu University |
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Principal Investigator |
S Prabakaran 九州大学, カーボンニュートラル・エネルギー国際研究所, 学術研究員 (80756429)
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| Project Period (FY) |
2015-08-28 – 2017-03-31
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| Keywords | graphene oxide / superlubricity / environments / nanostructures / hydrogen |
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| Outline of Annual Research Achievements |
1) We have developed multilayer polyethylenimine / graphene oxide thin films by a highly scalable layer by layer (LbL) deposition technique can be used as solid lubricants. The tribological properties are investigated in air, under vacuum, in hydrogen, and in nitrogen gas environments.
2) First time ever, ultra-low friction coefficients (Superlubricity regime, µ < 0.04) were observed in hydrogen and nitrogen for graphene oxide based coatings. The Tribological results show that the friction behavior in dry environment (vacuum, H2 and N2) is very different from humid environment (ambient air)
3) Microstructural analysis of the wear debris revealed that this is likely due to the formation of carbon nanoparticles in dry conditions (N2, vacuum), but not in the presence of moisture (air, H2). Such nanoparticles reduce the COF by introducing asperities and thereby decreasing the contact area.
4) The mechanism behind this microstructural difference was elucidated via density functional theory (DFT) simulations, which showed that strong hydrogen bonding occurs between graphene oxide sheets under pressure and in the presence of water, preventing the formation of nanostructures.
5) This work was accepted for oral presentation in STLE 2016 and Manuscript on this work will be submitted soon.
(Note : Confidential)
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| Current Status of Research Progress |
Current Status of Research Progress
1: Research has progressed more than it was originally planned.
Reason
1. Collaborative research enabled by various divisions such as CO2 capture and utilization (CCU) division and Electrochemical Energy Conversion (EEC) division of I2CNER.
2. Facilities, knowledge and expertiese were shared and provided by Kyushu University mechanical engg. staffs and Hydrogenius
3. Research friendly environment created by I2CNER management and staffs were also helpful.
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| Strategy for Future Research Activity |
1) Further investigation in effect of hydrogen during sliding is necessary.
2) Further characterization of nano-shells in dry environments is necessary
3) In-situ raman or environmental SEM can be done to assess the morphology of coatings with respect to environments.
4) More wear resistant coatings can be made by optimizing the conditions such as binding the GO chemically.
5) Optimum moisture content at which the tribology changes drastically.
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