1. School of Materials and Architectural Engineering, Guizhou Normal University, Guiyang 550001, P. R. China
2. Guizhou Engineering Research Center for Carbon Materials of Aluminum Electrolysis, Guizhou Normal University, Guiyang 550001, P. R. China
3. School of Materials and Metallurgical, Guizhou University, Guiyang 550025, P. R. China