1. State Key Laboratory of Solidification Processing, Centre of Advanced Lubrication and Seal Materials, Northwest Polytechnical University, Xi’an, Shaanxi 710072, PR China
2. State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Science, Gansu Lanzhou 730000, PR China
3. Qingdao Centre of Resource Chemistry and New Materials, Qingdao, Shandong 266100, PR China