1. Department of Materials Science and Engineering, New Energy and Material college, China University of Petroleum-Beijing, Beijing 102249, P. R. China
2. Beijing Key Laboratory of Failure, Corrosion, and Protection of Oil/Gas Facilities, China University of Petroleum-Beijing, Beijing 102249, P. R. China
3. State Key Laboratory of Tribology, Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China