1. Institute of Machine Design and Tribology, Leibniz University Hannover, 30823 Garbsen, Germany
2. Institute of Manufacturing Technology and Machine Tools, Leibniz University Hannover, 30823 Garbsen, Germany
3. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, China
4. Qingdao Center of Resource Chemistry and New Materials, Qingdao 266100, China