9月19日に、峯洋二教授(熊本大学大学院先端科学研究部)が世話人となり、第９９回IROASTセミナーが開催され、学内の教員及び学生が参加しました。ドイツのカールスルーエ工科大学からお越しのMartin Dienwiebel教授が、「高負荷グラファイト接点の湿度依存性」に関する興味深い講演をおこないました。

On September 19, 2023, the 99th IROAST Seminar, organized by Prof. Yuji MINE (FAST, Kumamoto University), was held and faculty members and students on campus attended. Prof. Martin Dienwiebel, Karlsruhe Institute for Technology (KIT), Germany, gave an informative talk on "On the humidity dependence of highly loaded graphite contacts".

■Opening Address | 開式挨拶

熊本大学 先端科学研究部 峯　洋二　教授
Professor Yoji MINE, FAST,  Kumamoto Uniersity

■Lecture|講演

カールスルーエ工科大学 (KIT)（ドイツ） Martin Dienwiebel教授 
 Prof. Martin Dienwiebel, Karlsruhe Institute for Technology (KIT), Germany

■At Venue|会場の様子

■Q&A｜質疑応答　

■Group Photo|集合写真 

The 99th IROAST Seminar 第99回IROASTセミナー開催のお知らせ

　国際先端科学技術研究機構（IROAST）は、カールスルーエ工科大学所属、Martin Dienwiebel教授による、第99回IROASTセミナーを下記のとおり開催いたします。
興味のある方はどなたでもご参加いただけます。多くの皆さまのご参加をお待ちしております。
本セミナーは英語にて行います。事前登録は不要です。

1．日　時：令和5年９月19日（火）10:30～12:00

2．会　場：黒髪南C3 59番 (工学部研究棟Ⅰ)　　308講義室

3．講演者・演題 (Title)：

カールスルーエ工科大学 (KIT)（ドイツ） Martin Dienwiebel教授 
“On the humidity dependence of highly loaded graphite contacts”

4．概要 (Abstract)：

Graphite is a well-known solid lubricant that has been studied for decades. At low loads, graphite’s lubricity depends on humidity. Classical models like e.g. the adsorption model explains this by molecular water films on graphite leading to defect passivation and easy sliding of counter bodies [1]. To explore the humidity dependence and validate the adsorption model for high loads (loads around 1 GPa as typically found in rolling bearing elements), a commercial graphite solid lubricant was studied using microtribometry [2]. Even at very high contact pressures, a high and low friction regime is observed - depending on humidity.

Transmission electron microscopy (TEM) and Electron Energy Loss spectroscopy (EELS) reveal transformation of the polycrystalline graphite lubricant into turbostratic carbon after high but also after low load (50 MPa) sliding. Quantum molecular dynamics simulations relate high friction and wear to cold welding and shear-induced formation of turbostratic carbon, while low friction originates in molecular water films on surfaces. The combined experiments and simulations lead to a novel, generalized adsorption model including turbostratic carbon formation.

[1] Savage, R. H. Graphite lubrication. J. Appl. Phys. 19, 1–10 (1948).
[2] C. Morstein, A. Klemenz, M. Dienwiebel, M. Moseler, Nature Comm. 13, 2022

5．世話人： 峯　洋二　教授　（大学院先端科学研究部）
                     （Email：mine@msre.kumamoto-u.ac.jp）

【IROASTセミナーに関するお問合せ】

佐藤
Email: szk-kiko@jimu.kumamoto-u.ac.jp

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IROAST will have the 99th IROAST Seminar by Prof. Martin Dienwiebel, Karlsruhe Institute of Technology, Germany as follows.
Anyone interested in this seminar is more than welcome. Registration is not required.

We hope to see you at the seminar.

1. Date and time: September 19 (Tue), 2023, 10:30-12:00
2. Venue: Room 308, Kurokami South C3 (Faculty of Engineering Research Bldg. I)
3. Speaker: Prof. Martin Dienwiebel, Karlsruhe Institute for Technology (KIT), Germany
4. Title & Abstract: Referred to above
5. Organizer: Prof. Yoji Mine (FAST, Kumamoto University)
                        E-mail: mine@msre.kumamoto-u.ac.jp
6. Remarks: This seminar will be held in English.

[IROAST Seminar inquiries]

Sato (Ms.)
szk-kiko@jimu.kumamoto-u.ac.jp